DETAILED ACTION
Status of Application
Acknowledgement is made of amendments filed 07/08/2026. Upon entering the amendments, claims 21-23 are added and claims 7-8, 11, and 13-20 are amended. The claims 1-23 are pending and presented for the examination.
Information Disclosure Statement
2. The information disclosure statement (IDS) submitted on 07/08/2026 was filed after the mailing date of the Non-Final Office Action on 04/09/2026. The submission is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Claim Rejections - 35 USC § 103
3. 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.
4. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
5. 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.
6. Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Arai et al (US 2020/0012042 A1) in view of Bennett et al (US 8488932 B2).
Regarding claim 13, Arai et al teaches a glass microparticulate comprising quartz glass. The quartz glass is taught to comprise fluorine as a dopant (see paragraph 0173). The fluorine-containing silica glass powder taught by Arai et al has a particle size of 50-500 µm, with an embodiment taught having a 200 µm particle size (see paragraph 0047). Because this is the average particle size and the diameter falls within the range of the instant claim, the Arai et al glass particulate constitutes a powder having a particle size of 150-300 µm. This new limitation of the claim is interpreted to indicate average particle size; however, the limitation could also reasonably cover any particulate wherein some portion of the particles have a size in the 150-300 µm range. Such a powder would thus have “a particle size” in the claimed ranged. As such, the Arai et al particulate meets the new particle size limitation of the instant claim.
The claim differs from Arai et al because Arai et al does not specify fluorine concentration, and thus does not teach a content of at least 2 wt%. However, it would have been obvious to one of ordinary skill in the art to modify Arai et al in view of Bennett et al in order to use the fluorine contents taught therein. Bennett et al teaches an optical fiber comprising core and cladding portions, wherein fluorine is used as a dopant in the overclad layer (see column 6, lines 10-15) so as to modify viscosity and refractive index of the cladding relative to the surrounded portion (see column 4, lines 44-55). Bennett et al teaches contents of fluorine doping greater than 2 wt% (see Table 1A). Because of the lack of specificity in the teaching regarding fluorine doping in Arai et al, one of ordinary skill would have been motivated to look to other teachings in the prior art for appropriate fluorine contents. Bennett et al provides such a teaching. One of ordinary skill would have found particular motivation and a reasonable expectation of success in the combination because Arai et al teaches a clad made of a silica glass comprising a fluorine dopant for lowering refractive index (see paragraph 0173), and Bennett et al provides a teaching as to fluorine contents used in refractive index adjustment doping. Each limitation of amended claim 13 is therefore met by the teachings of the prior art of record, and the claim is obvious and not patentably distinct.
Allowable Subject Matter
7. Claims 1-12 and 14-23 are allowed. The prior art, either alone or in combination, fails to teach or suggest a fluorine-containing silica glass powder comprising particles having a particle size of 150-300 µm in an amount of 25% by weight or more as a whole. The prior art also does not teach or suggest a method of producing a fluorine-containing silica glass powder comprising removing water and hydroxy groups from a silicon oxide by heating, before introducing SiF4, prefiring a silicon oxide at a temperature of lower than 1,000°C in the presence of SiF4 to prepare a fluorine-containing silica, and firing the fluorine-containing silica at a temperature of 1,000°C-1,400°C to produce a silica glass powder, wherein the temperature is lower than a softening point of the fluorine-containing silica by at least 50°C. The prior art further does not teach or suggest a method of producing a fluorine-containing silica glass powder comprising mixing a silicon oxide with an ammonium fluoride to obtain a mixed solid powder, wherein the ammonium fluoride has a particle size of 1 mm or less, prefiring the mixed solid powder at a temperature of 750°C or lower to obtain a fluorine-containing silica; and firing the fluorine-containing silica at 1,000°C-1,400°C to obtain a silica glass powder, wherein the temperature is lower than a softening point of the fluorine-containing silica by at least 50°C. Finally, the prior art does not teach or suggest a method of producing a fluorine-containing silica glass powder comprising maintaining a silicon oxide at a first temperature prior to prefiring the silicon oxide in the presence of a fluorocarbon, prefiring the silicon oxide at a second temperature in the presence of the fluorocarbon to form a fluorine-containing silica, annealing the fluorine-containing silica at a third temperature, and annealing, firing the fluorine-containing silica at a fourth temperature to form a silica glass powder, wherein the first temperature is in a range of 850°C or lower, the second temperature is in a range of 850°C or lower, the third temperature is equal to or lower than the fourth temperature, and the fourth temperature is in a range of 1,000°C or higher.
Response to Arguments
8. Applicant’s arguments filed 07/08/2026 have been fully considered. The remarks are persuasive regarding the previously issued anticipation rejections over the prior art to Arai et al and regarding the rejection over Fukazawa et al as it pertains to amended claim 13. These grounds are therefore withdrawn. The obviousness rejections of claims 2 and 5-7 over Arai et al as primary reference are therefore also shown to be overcome, as said claims depend from independent claim 1. The remarks are further persuasive at showing the patentability of amended claims 8 and 16, and the claims depending therefrom, over the previously applied prior art to De Hazen et al, both alone and in combination with the secondary pieces of prior art discussed in the previous Office Action. These obviousness rejections of said claims 8-12 and 14-18 are therefore withdrawn. Finally, the remarks are persuasive regarding amended claim 19, in that they show that each limitation of said amended claim is not taught or suggested by the applied prior art to De Hazan et al and Rabinovich. The previously issued grounds of rejection for said claim and the claims depending therefrom are thus withdrawn.
Regarding claim 13, while the arguments are persuasive at showing that the amended claim is no longer anticipated by Fukazawa et al, a new ground of rejection is set forth for said claim, as discussed above. This new ground is necessitated by the amendments to the claim.
Conclusion
9. Claims 1-12 and 14-23 are allowed. Claim 13 is rejected.
10. 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 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.
11. Any inquiry concerning this communication or earlier communications from the examiner should be directed to NOAH S WIESE whose telephone number is (571)270-3596. The examiner can normally be reached on Monday-Friday, 7:30am-4:30pm.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Amber Orlando can be reached on 571-270-3149. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/NOAH S WIESE/Primary Examiner, Art Unit 1731
NSW15 September 2026
