Prosecution Insights
Last updated: April 19, 2026
Application No. 18/001,447

GLASS COMPOSITION FOR CHEMICAL STRENGTHENING AND CHEMICALLY STRENGTHENED GLASS ARTICLE

Final Rejection §103
Filed
Dec 09, 2022
Examiner
MAYES, MELVIN C
Art Unit
1759
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Nippon Sheet Glass Company, Limited
OA Round
2 (Final)
30%
Grant Probability
At Risk
3-4
OA Rounds
4y 8m
To Grant
29%
With Interview

Examiner Intelligence

Grants only 30% of cases
30%
Career Allow Rate
35 granted / 115 resolved
-34.6% vs TC avg
Minimal -2% lift
Without
With
+-1.6%
Interview Lift
resolved cases with interview
Typical timeline
4y 8m
Avg Prosecution
20 currently pending
Career history
135
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
52.6%
+12.6% vs TC avg
§102
18.6%
-21.4% vs TC avg
§112
20.8%
-19.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 115 resolved cases

Office Action

§103
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 . Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claims 1-12, 14, 16-19 and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Miyasaka et al. (US 2017/0121220). Regarding claims 1-6, Miyasaka et al. disclose a glass composition comprising: 63 to 76 wt% SiO2 0 to 2 wt% B2O3 2 to 10 wt% Al2O3 2 to 12 wt% MgO 0.1 to 8 wt% CaO 14.5 to 19 wt% Na2O 0 to 3 wt % K2O 0 to 0.5 Fe2O3, satisfying a total content (RO) of alkali earth metal oxides being from 5 to 15, satisfying 15×MgO/RO—RO≧3, and having a temperature T2 at which a glass viscosity reaches 102 dPa.s being 1,600° C. or lower [0012]-[0023]. The wt% ranges of SiO2, Al2O3, MgO, CaO, Na2O, K2O and SrO overlap the claimed mol% ranges, thus prima facie obviousness. 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); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). It would have been obvious to one of ordinary skill in the art for the effective filing date to select wt% and thus mol% within the claimed ranges that satisfy the conditions required for the glass composition. Regarding claims 2, 5 and 6, Miyasaka et al. disclose providing the glass composition with a specific gravity (density) of 2.55 or less, further preferably 2.50 or less, for using the glass after a chemical toughening treatment in applications such as cover glass [0077]-[0078], and exemplifies 2.40-2.47, examples 1-9. Regarding claim 7, Miyasaka et al. disclose total content (RO) of alkali earth metal oxides being from 5 to 15, and exemplifies glass composition comprising 0% SrO and BaO, examples 1-9. Regarding claim 8, Miyasaka et al. exemplifies glass composition comprising 9 to 20 mol% MgO+CaO, examples 1 and 7. Regarding claim 9, Miyasaka et al. exemplifies glass composition having molar ratio in the range of 0.91 to 1, example 7. Regarding claim 10, Miyasaka et al. exemplifies glass composition having 15.5 to 25 mol% Na2O+K2O, example 7. Regarding claim 11, Miyasaka et al. exemplifies glass composition having molar ratio in the range of 0.61 to 1, examples 1 and 7. Regarding claim 12, Miyasaka et al. exemplifies glass composition having molar ratio in the range of 0.015 to 0.072, examples 1 and 7. Regarding claim 14, Miyasaka et al. discloses providing the glass composition with T2 of 1600C or lower, more preferably 1550C or lower [0069] and exemplifies 1492C – 1548C, examples 1-9, overlapping the claimed range, thus prima facie obviousness. Regarding claim 16, Miyasaka et al. discloses providing the glass composition with coefficient of thermal expansion CTE of 100x10-7 or less [0075] and exemplifies CTE of 93x10-7/C, example 1, overlapping the claimed range, thus prima facie obviousness. Regarding claim 17, Miyasaka et al. discloses providing the glass composition with Tg of 520C or higher [0074] and exemplifies Tg of 580C and 543C, examples 1 and 7, overlapping the claimed range, thus prima facie obviousness. Regarding claims 18 and 19, Miyasaka et al. discloses providing chemically strengthened glass with surface compressional stress (CS) of 300 MPa or more, preferably 700 MPa or more [0083], and compressive stress layer depth (DOL) of 8 um or more, preferably 25 um or less [0080]-[0081] and exemplifies surface compressive stress (CS) of 807 MPa (example 3) and exemplifies DOL of 21.8 um, example 7. Regarding claim 21, Miyasaka et al. discloses providing chemically strengthened glass with surface compressional stress (CS) of 300 MPa or more, preferably 700 MPa or more [0083] and exemplifies surface compressive stress (CS) of 807 MPa, and with compressive stress layer depth (DOL) of 8 um or more, preferably 25 um or less [0080]-[0081], which ranges of CS and DOL overlap the claimed CS and DOL relationship and encompasses the claimed CS range, thus prima facie obviousness. Claims 1-3, 7-12, 14, 15, 17-19 and 21 are rejected under 35 U.S.C. 103 as being unpatentable over Senshu et al (US 9,764,980) Regarding claim 1, Senshu et al. disclose a glass composition comprising in mol%: 66-72% SiO2, encompassed by claimed 60 to 80% 2-3% Al2O3, encompassed by claimed 1 to 5% 8-15% MgO, encompassed by claimed 5 to 25% 1-8% CaO, overlaps claimed 0 to 5% 12-16% Na2O, encompassed by claimed 10 to 20% 0-1% K2O, encompassed by claimed 0 to 10%, wherein total content of MgO and Cao is 12 to 17% and molar ratio of CaO to MgO+CaO is 0.1 to 0.4 (claim 1). The wt% range of CaO overlaps the claimed mol% range, thus prima facie obviousness. 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); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). It would have been obvious to one of ordinary skill in the art for the effective filing date to select mol% of CaO within the claimed range that satisfy the conditions required for the glass composition. Regarding claim 2, Senshu et al. disclose a glass composition comprising in mol%: 66-72% SiO2, encompassed by claimed 62 to 75% 2-3% Al2O3, encompassed by claimed 1 to 4.9% 8-15% MgO, encompassed by claimed 5 to 20% 1-8% CaO, overlaps claimed 0 to 1% 12-16% Na2O, overlaps claimed 15.5 to 19% 0-1% K2O, encompassed by claimed 0 to 10%, wherein total content of MgO and Cao is 12 to 17% and molar ratio of CaO to MgO+CaO is 0.1 to 0.4 (claim 1). Senshu et al disclose that for float process, the glass has density of 2.4 to 2.55 g/cm3 (col. 8, lines 61-67), overlapping the claimed range, thus prima facie obviousness.. The wt% ranges of CaO and Na2O overlap the claimed mol% ranges, thus prima facie obviousness. 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); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). It would have been obvious to one of ordinary skill in the art for the effective filing date to select mol% of CaO and Na2O and density of the glass within the claimed ranges that satisfy the conditions required for the glass composition. Regarding claim 3, Senshu et al. disclose a glass composition comprising in mol%: 66-72% SiO2, overlaps claimed 62 to 68% 2-3% Al2O3, overlaps claimed 2.5 to 4.9% 8-15% MgO, overlaps claimed 12 to 18% 1-8% CaO, overlaps claimed 0 to 1% 12-16% Na2O, overlaps claimed 15.5 to 19% 0-1% K2O, encompassed by claimed 0 to 1.5%, wherein total content of MgO and Cao is 12 to 17% and molar ratio of CaO to MgO+CaO is 0.1 to 0.4 (claim 1). The wt% ranges of SiO2, Al2O3, MgO, CaO and Na2O overlap the claimed mol% ranges, thus prima facie obviousness. 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); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). It would have been obvious to one of ordinary skill in the art for the effective filing date to select mol% of SiO2, Al2O3, MgO, CaO and Na2O within the claimed ranges that satisfy the conditions required for the glass composition. Regarding claim 7, Senshu et al disclose making the glass substantially free of SrO and BaO (col. 5, lines 17-19). Regarding claims 8 and 9, Senshu et al disclose 8-15% MgO and 1-8% CaO, thus overlapping claimed content and molar ratio ranges, thus prima facie obviousness. Regarding claims 10 and 11, Senshu et al disclose 12-16% Na2O and 0-1% K2O, thus overlapping claimed content and molar ratio ranges, thus prima facie obviousness. Regarding claim 12, Senshu et al disclose 66-72% SiO2 and 2-3% Al2O3, thus overlapping claimed molar ratio range, thus prima facie obviousness. Regarding claim 13, Senshu et al. disclose making examples, all with Young’s modulus of 72 to 74 GPa and density of 2.448 to 2.499 g/cm3, thus specific elastic modulus (Young’s modulus/density) of 29 x 106 to 30 x 106 Nm/kg. Thus providing any glass composition withing the range disclosed by Senshu et al. with similar properties of Young’s modulus and specific elastic modulus would have been obvious to one of ordinary skill in the art as suggested by Senshu et al. as desired properties for the glass compositions for chemical strengthening. Regarding claim 14, Senshu et al disclose T2 of 1550C or lower (claim 5). Regarding claim 15, Senshu et al disclose T4 of 1100C or less (claim 4) and difference between T4 and liquidus temperature of -30C or more (col. 8, lines 33-46) overlapping the claimed ranges, thus prima facie obviousness.. Regarding claim 17, Senshu et al disclose a lowered glass transition temperature (Tg) of 610° C. or less and the lower limit of the glass transition temperature may be 530° C. or more (col 7, line 65 – col 8, line 5) overlapping the claimed range, thus prima facie obviousness. Regarding claims 18 and 19, the chemically strengthened glass article made from the glass has surface compressive stress of 700 MPa or more and compressive stress layer depth of 20 um or more (claim 12) overlapping the claimed ranges, thus prima facie obviousness. Regarding claim 21, Senshu et al discloses providing chemically strengthened glass with surface compressional stress (CS) of 700 MPa or more, and with compressive stress layer depth (DOL) of 20 um or more, which ranges of CS and DOL overlap the claimed CS and DOL relationship and encompasses the claimed CS range, thus prima facie obviousness. Response to Arguments Applicant's arguments filed October 30, 2025 have been fully considered but they are not persuasive. Regarding the Claim Rejections - 35 U.S.C.103 over Miyasaka: Applicant argues that the glass composition for chemical strengthening according to claim 1 can be used to produce a glass sheet by a common float process and can provide a glass sheet with both the surface compressive stress and the compressive stress layer depth in appropriate ranges (see paragraph [0008] on page 2 of the specification as filed). These beneficial features are achieved by controlling the contents of CaO, Na2O, and SiO2 as discussed below: Applicant argues that by including CaO at "0 to 1%," not only is devitrification of the glass suppressed, but also a decrease in the surface compressive stress after chemical strengthening is suppressed, and a decrease in the chemical resistance of the glass, such as the alkali resistance, is suppressed (see paragraph [0015] on page 4 of the specification). With respect to the CaO content, Miyasaka is silent regarding the relationship between the content of CaO and the surface compressive stress after chemical strengthening or the relationship with the chemical resistance of glass. Accordingly, a person skilled in the art would not have had any reason to choose the content of CaO of 0 to 1 mol% from Miyasaka's broad disclosure of 0.1 to 8 wt%, nor would have been motivated to choose 0 to 1 mol%, which does not include the amount of CaO used in Miyasaka's Example 1. The argument is not convincing because similar to Applicant with range of 0-5 mol%, now limited to preferable range of less than 1%, Miyasaka also teaches that the CaO content has an effect on devitrification, and is preferably as low as possible to prevent warping, preferably less than 1% mass% [0050]. Applicant argues that by including Na2O at "15.5 to 19%," the water resistance of the glass is prevented from becoming too low, and the meltability of the glass is also prevented from decreasing (see paragraph [0018] on pages 4-5). With respect to the Na2O content, Miyasaka is silent regarding the relationship between content of the Na2O and the water resistance of glass. Accordingly, a person skilled in the art would not have had rational basis to choose the content of Na2O of 15.5 to 19 %, which does not include the amount used in Example 1, nor would have been motivated to increase the content of Na2O to "15.5 to 19%," which does not include the amount used in Example 1. The argument is not convincing because similar to Applicant with range of 10-20 mol% now limited to preferable range of 15.5 to 19%, Miyasaka also teaches that NaO affects weather resistance and should be 19% or less and is more preferably 15.5% or more [0052]. Applicant argues that by including SiO2 at "62 to 68%," the deterioration of the meltability of the glass is suppressed, and the devitrification and deterioration of the weather resistance of the glass are also suppressed (see paragraph [0011] on page 3). With respect to the SiO2 content, although Miyasaka mentions that the content of SiO2 is 63 to76 wt%, the amount in Example 7 is approximately 71.87 mol%, which is above 62-68% required by claim 1. Miyasaka further discloses that 68 wt% or more is preferred, i.e., the higher the content the better (see paragraph [0042] on page 2). Therefore, a person skilled in the art would not have had any reason to choose the amount of 62-68% nor would have been motivated to reduce the content of SiO2 to 62 to 68%, which does not include the amount used in Example. The argument is not convincing because similar to Applicant with range of 60-80 mol% now limited to preferable range of 62 to 68%, Miyasaka also teaches that SiO2 affects weather resistance and meltability and should be 64% or more and preferably 75% or less [0042]. Applicant argues that the closest examples of Miyasaka that allegedly satisfy the conditions recited in claim 1 are Examples 1 and 7 in Table 1. However, as discussed above, Example 1 of Miyasaka does not satisfy 0 to 1% CaO and 15.5 to 19% Na2O required by claim 1, and Example 7 of Miyasaka does not satisfy 62-68% of SiO2 required by claim 1. The argument is not convincing because Miyasaka disclosure and suggestions are not limited to its Examples, and further the amounts of CaO (1.05 mol%) and Na2O (15.37 mol%) with 66.95% SiO2 in Example 1 are close to the claimed ranges of content, thus a suggestion that 1% CaO and 15.5% Na2O would have been obvious to one of ordinary skill in the art to provide with SiO2 content in the claimed range. Regarding the Claim Rejections - 35 U.S.C.103 over Senshu: The closest example of Senshu that allegedly satisfies the conditions recited in claim 1 is Example 2 in Table 1. However, as discussed above, Example 2 of Senshu contains 2.8 mol%CaO and 70.0 mol% of SiO2, which are outside of the range required by claim 1. With respect to the CaO content, Senshu broadly recites that the CaO content is 1 to 8 mol%, which only touches the range recited in claim 1 (0 to 1%). Furthermore, the closest example, Example 2, contains 2.8% of CaO, and Senshu does not suggest that a glass composition with the desirable properties enjoyed by claim 1 can be obtained with 1 mol% of CaO. Accordingly, a person skilled in the art would not have had any reason to limit the CaO content to 0 to 1% nor would have had reasonable expectation of success by reducing the CaO content to 0 to 1 %. The argument is not convincing because Senshu teaches 1 to 8 mol% CaO (overlaps the claimed 0 to 1%) as long as the requirements of MgO and CaO content of 12 to 17% and Cao/MgO molar ratio of 0.1 to 0.4 is met to decrease viscosity without significantly decreasing surface compressive stress, thus reasonable expectation of success in achieving those desirable properties by providing CaO content of 1%. Applicant argues that with respect to the SiO2 content, Senshu's Example 2 has a SiO2 content of 70.0 mol%, which is above the range of 62-68 mol% required by claim 1. There is no disclosure in Senshu providing any reason for a person skilled in the art to limit the SiO2 content to 62-68 mol% nor to have reasonable expectation of success in achieving desirable properties by limiting the SiO2 content to 62-68 mol%. The argument is not convincing because Senshu provides reasoning to limit content to mol% within the claimed range because Senshu teaches range of 66 to 72% and preferably 67 to 70% (overlaps the claimed 62 to 68%), as too low reduces chemical durability and too high increases viscosity, thus reasonable expectation of success in achieving those desirable properties by providing SiO2 content of 66 to 68%. Applicant argues that with respect to the Na2O content, Senshu's Example 2 has a Na2O content of 13.2 mol%, which is below 15.5-19 mol% required by claim 1. There is no disclosure in Senshu providing any reason for a person skilled in the art to limit the Na2O content to 15.5-19 mol% nor to have a reasonable expectation of success in achieving desirable properties by limiting the Na2O content to 15.5-19 mol%. The argument is not convincing because Senshu teaches content of 12 to 16 mol% (overlaps claimed 15.5 to 19%) for sufficient effect on reducing T4 and T2 yet without marked reduction in surface compressive stress due to stress relaxation, thus reasonable expectation of success in achieving desirable properties by providing Na2O content of 15.5 to 16 mol%. Conclusion THIS ACTION IS MADE FINAL. 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 nonprovisional extension fee (37 CFR 1.17(a)) 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 mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to MELVIN C MAYES whose telephone number is (571)272-1234. The examiner can normally be reached Mon-Fri 8:00am - 4:30pm. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Yvonne L Eyler can be reached at (571)272-1200. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /MELVIN C. MAYES/Supervisory Patent Examiner, Art Unit 1759
Read full office action

Prosecution Timeline

Dec 09, 2022
Application Filed
Jul 29, 2025
Non-Final Rejection — §103
Oct 30, 2025
Response Filed
Jan 26, 2026
Final Rejection — §103 (current)

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Prosecution Projections

3-4
Expected OA Rounds
30%
Grant Probability
29%
With Interview (-1.6%)
4y 8m
Median Time to Grant
Moderate
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