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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 5 January 2026 has been entered.
Claim Objections
Claim 1 is objected to because of the following informalities: claim 1 recites in lines 3-4 “B2O3 present in an amount up to 7 wt% of B2O3” which appears to be a typographical error. The examiner suspects the intent of the applicant was to recite this portion of claim 1 as “B2O3 present in an amount up to 7 wt%” and will be examined on the merits as such.
Appropriate correction is required.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
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.
Claims 1-3, 5-9, 12-18, 24, 26 and 27 are rejected under 35 U.S.C. 103 as being unpatentable over United States Patent Application Publication No. US 2005/0090377 (hereinafter “Shelestak”), in view of United States Patent Application Publication No. US 2018/0127302 (hereinafter “Gross”), and further in view of United States Patent Application Publication No. US 2016/0102011 (hereinafter “Hu”).Regarding claims 1-3 Shelestak teaches a glass composition for chemical tempering which results is a chemically tempered glass (glass article) (abstract). Shelestak teaches the glass is chemically strengthened, where a compressive stress is introduced at the surface of the glass (paragraph [0005]), which corresponds to the glass being chemically prestressed. Shelestak also teaches the glass is a glass sheet which may be used as an aircraft or vehicle transparency (paragraphs [0037] and [0106]), which corresponds to a plate-shaped or disc-shaped glass article. Shelestak teaches the glass composition comprises Al2O3, SiO2, B2O3, P2O5, Na2O, Li2O, and MgO, where B2O3 ranges from 0-1.75 wt%, which falls within the claimed range, P2O5 ranges from 0-1.75 wt%, which falls within the claimed range, Na2O ranges from 0-3 wt%, which overlaps the claimed ranges, Li2O ranges from 3-9 wt%, which encompasses the claimed range, and MgO ranges from 0-3 wt%, which encompasses the claimed range (abstract and paragraphs [0009] – [0021]). Shelestak teaches the glass composition is prestressed using molten nitrate baths (ion exchange baths) including potassium salts, sodium salts, and combinations thereof (paragraph [0087]). Shelestak generally teaches the time period of the chemical strengthening baths are 8-22 hours, at a preset temperature (paragraph [0088] and Table 3). Shelestak does not explicitly teach a degree of chemical strengthening, such as a compressive prestress (CS) on the surface of the glass article of at least 600 MPa and a prestressing in relation to the weight percent of Na2O of at least 250 MPa/g Na2O and at most either 1000 or 1500 MPa/g Na2O in 100g of glass, a thickness of at most 2.0 mm, or the glass article has been prestressed using, in sequence, a first ion exchange bath having sodium for at least 2 hours and a second ion exchange bath having potassium for at least 1 hour. Gross teaches a glass article which is chemically strengthened to be more resistant to failure by introducing a compressive stress (prestressed) in the glass surface (paragraph [0005]). Gross teaches a thickness of the glass article ranges from 0.82-1.078 mm (Table 3), which falls within the claimed range. Gross teaches the glass article is useful in aircraft applications (paragraph [0249]). Gross teaches the chemical strengthening process includes a molten salt bath (e.g., KNO3 (ion exchange bath having potassium) and/or NaNO3 (ion exchange bath having sodium)) which imparts high strength, high toughness, and high indentation cracking resistance to the strengthened glass (paragraphs [0204], [0242], and [0259]). Gross teaches the glass composition is physically exposed to an ion exchange solution bath for a duration ranging from 4-48 hours (paragraph [0243]). Gross teaches the ion exchange process may be performed under processing conditions that provide an improved compressive stress profile, as disclosed by Hu which is incorporated herein by reference in its entirety (paragraph [0244]). Hu teaches an ion exchange process includes a glass-based article that is immersed in a molten bath of, for example, NaNO3 for 15 min to 100 hours (first ion exchange bath having sodium for at least 2 hours, which overlaps the claimed range), depending on the thickness of the glass, bath temperature and glass diffusivity, and, in some embodiments, may include immersion in a second bath of KNO3 for 15 min to 8 hours (second ion exchange bath having potassium for at least 1 hour, which overlaps the claimed range) (paragraphs [0088] – [0089]), corresponding to the glass article has been prestressed using, in sequence, a first ion exchange bath having sodium for at least 2 hours and a second ion exchange bath having potassium for at least one hour. Gross teaches the glass article is strengthened by an ion exchange process, where the compressive stress at the surface ranges from 300-950 MPa (paragraph [0015]), which overlaps the claimed range. Gross does not explicitly teach the prestressing of the glass article is in relation to the weight percent of Na2O of at least 250 MPa/g Na2O and at most 1000 or 1500 MPa/g Na2O in 100 g of glass. However, it would have been obvious to one having ordinary skill in the art at the time of the invention to determine the degree of compressive stress (prestressing) present in the glass article based on the glass composition using nothing more than routine experimentation to achieve the desired strengthening of the glass article for its intended application. It has been held where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art unless such a range is shown to be critical. Please see MPEP § 2144.05(II)(A). Shelestak, Gross and Hu are analogous inventions in the field of chemically strengthened glass articles for aircraft applications. It would have been obvious to one skilled in the art at the time of the invention to modify the glass article of Shelestak with the chemical strengthening process, resulting in the compressive stress layers and thickness, of Gross and Hu to improve the compressive stress profile and/or tailor the strength of the glass article for an aircraft application. Moreover, the use of product-by-process limitations have been noted in claim 1, for example, "the glass article has been prestressed using, in sequence, a first ion exchange bath having sodium for at least 2 hours and a second ion exchange bath having potassium for at least 1 hour." "[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process", In re Thorpe, 777 F.2d 695, 698, 227 USPQ 964, 966 (Fed. Cir. 1985). Further, "although produced by a different process, the burden shifts to applicant to come forward with evidence establishing an unobvious difference between the claimed product and the prior art product", In re Marosi, 710 F.2d 798, 802, 218 USPQ 289, 292 (Fed. Cir.1983). See MPEP § 2113.Regarding claim 5 In addition, Shelestak teaches SiO2 is present in an amount of 60-75 wt% (abstract), which overlaps the claimed range.Regarding claim 6 In addition, Shelestak teaches Al2O3 is present in an amount of 18-28 wt% (abstract), which overlaps the claimed range.Regarding claim 7 In addition, Shelestak teaches SiO2 is present in an amount of 60-75 wt% and Al2O3 is present in an amount of 18-28 wt% (abstract), which corresponds to a sum of SiO2 and Al2O3 ranging from 78-97 wt%, which overlaps the claimed range.Regarding claim 8 In addition, Shelestak teaches the following concentrations of the network formers (SiO2, Al2O3, B2O3, and P2O5): 60-75 wt% of SiO2; 18-28 wt% of Al2O3; 0-1.75 wt% of B2O3; and 0-1.75 wt% of P2O5 (abstract and paragraph [0047]), which corresponds to the network formers ranging from 78-97 wt%, which overlaps the claimed range.Regarding claim 9 In addition, Shelestak teaches the following concentrations of the alkali oxides (Li2O, Na2O, and K2O): 3-9 wt% of Li2O; 0-3 wt% of Na2O; and 0-0.5 wt% of K2O (abstract), which corresponds to the total content of alkali oxides ranging from 3-12.5 wt%, which encompasses the claimed range.Regarding claims 12 and 13 In addition, Shelestak teaches the glass comprises: 60-75 wt% of SiO2; 18-28 wt% of Al2O3; 3-9 wt% of Li2O; and 0-3 wt% of Na2O, where the sum of a content of Al2O3 and SiO2 corresponds to a range of 78-97 wt% (abstract), where each range either overlaps or encompasses their respective claimed range.Regarding claim 14 In addition, Gross teaches a thickness of the glass article ranges from 0.82-1.078 mm (Table 3), which overlaps the claimed range.Regarding claim 15 Regarding the acid resistance of the glass article, although the prior art does not explicitly disclose the glass article comprises an acid resistance determined as a half weight loss per unit area in mg/dm2 in a test in accordance with DIN 12116 that is no more than 15 mg/dm2, the claimed property is deemed to naturally flow from the structure in the prior art since the combination of Shelestak, Gross and Hu teaches an invention with an identical and/or substantially identical structure and/or chemical composition as the claimed invention. See MPEP §2112.Regarding claim 16 In addition, Shelestak teaches the glass article may be useful in a transparency for a vehicle (safety glass, automobile glazing, etc.) (paragraph [0106]). Gross also teaches the glass article may be useful in a display article (e.g., consumer electronics, including mobile phones, tablets, computers, navigation systems, and the like), transportation articles (e.g., automotive, trains, aircraft, sea craft, etc.), appliance articles, or any article that requires some transparency, scratch-resistance, abrasion resistance or a combination thereof (paragraph [0249]).Regarding claims 17 and 18 In addition, Shelestak teaches the glass composition comprises: 60-75 wt% of SiO2; 18-28 wt% of Al2O3; 3-9 wt% of Li2O; and 0-3 wt% of Na2O, where the sum of a content of Al2O3 and SiO2 corresponds to a range of 78-97 wt% (abstract), where each range either overlaps or encompasses their respective claimed range. The limitation requiring “the weight percent of Na2O is at least 0.8 so that the glass is amenable to a potassium ion exchange” has been considered. However, this limitation fails to provide any additional structure to the claimed glass article. This limitation merely describes what happens to the glass article when the weight percentage of Na2O is at the claimed level. Therefore, although the prior art does not explicitly disclose the weight percentage of Na2O is at least 0.8 so that the glass is amenable to a potassium ion exchange, the claimed property is deemed to naturally flow from the structure in the prior art since the combination of Shelestak, Gross and Hu teaches a glass composition with an identical or substantially identical chemical composition as the claimed composition. See MPEP §2112.Regarding claims 24, 26 and 27 In addition, Shelestak teaches the glass composition comprises K2O ranging from 0-0.5 wt%, which falls within the claimed range (abstract). The claimed range of SrO includes a value of 0 wt%; therefore, SrO is considered to be an optional element and not required to meet the claims.
Claims 26 and 27 are rejected under 35 U.S.C. 103 as being unpatentable over Shelestak, Gross and Hu as applied to claim 1 above, and further in view of United States Patent Application Publication No. US 2017/0107141 (hereinafter “Miyasaka”).Regarding claims 26 and 27 The limitations for claim 1 have been set forth above. In addition, Shelestak teaches the glass composition comprises K2O ranging from 0-0.5 wt%, which falls within the claimed range (abstract). The combination of Shelestak and Gross does not explicitly teach an SrO content ranging from >0 wt% to 1.5 wt%. Miyasaka teaches a glass for chemical strengthening useful in an aircraft application (abstract and paragraph [0150]). Miyasaka teaches SrO in the glass composition provides an effect of decreasing viscosity of glass in melting to accelerate melting and improve the devitrification property, and can be included in a content of 1 mass% (wt%) or less, which falls within the claimed range (paragraphs [0023] and [0090]). Shelestak, Gross and Miyasaka are analogous inventions in the field of chemically strengthened glass compositions. It would have been obvious to one skilled in the art at the time of the invention to modify the glass composition from the combination of Shelestak and Gross with the SrO content of Miyasaka to accelerate melting and improve the devitrification property of the glass.
Response to Arguments
Applicant's arguments filed 5 January 2026 have been fully considered but they are not persuasive.
The applicant provided a table comparing the content of B2O3, P2O5, Na2O, Li2O, and MgO disclosed by Shelestak with the content present in claim 1. The applicant discussed that the teachings from Shelestak show that: (i) B2O3 is “most often absent;” (ii) P2O5 is “most often absent;” (iii) Na2O should be below claim 1 about half the time; (iv) Li2O should be above the claimed range which is more likely to produce a crystallized glass; and (v) while MgO can be absent, it can be present up to 2x the amount of claim 1. The applicant then argued (i) – (v) are 6 compositional differences between Shelestak and amended claim 1, and it would not have been obvious to make so many modification to Shelestak to arrive at the claims. First, the examiner respectfully disagrees and contends that the applicant’s apparent requirement of the examiner that broader teachings should be ignored because certain examples do not teach the broader elements has no legal basis. Second, in cases where disclosed ranges from the prior art encompass, fall within, overlap, or are merely close to claimed ranges, prima facie cases of obviousness exist. See MPEP § 2144.05(I). Third, the use of patents as references is not limited to what the patentees describe as their own inventions or to the problems with which they are concerned. They are part of the literature of the art, relevant for all they contain. A reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill the art, including nonpreferred embodiments. MPEP § 2123.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to BRIAN HANDVILLE whose telephone number is (571)272-5074. The examiner can normally be reached Monday through Thursday, from 9 am to 4 pm.
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/BRIAN HANDVILLE/Primary Examiner, Art Unit 1783
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