DETAILED ACTION
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 July 3, 2026 has been entered.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 1-9 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
Claim 1 recites the product of the time period and the linear speed is at least 13.6 (m) and less than or equal to 18.1 (m). The specification does not appear to offer support for this range. The specification offers support for the range of 15.5 m or more. The specification also recites a comparative example with a product value of 13.6. Thus, support for a range from 13.6 to 15.5 is not provided.
Claims 2-9 are indefinite by virtue of their dependencies on claim 1.
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.
Claims 1-9 and 13-21 are rejected under 35 U.S.C. 103 as being unpatentable over Grieco et al. (2023/0382781) in view of Lane et al. (4,741,748), with evidence by DeLuca (3,933,454). Regarding claims 1 and 13, Grieco teaches a method for producing optical fiber preform comprising manufacturing a glass fine particle deposit (porous glass preform) by an outside vapor deposition process ([0002]-[0003]). Grieco doesn’t offer specifics on the outside vapor deposition process, but does reference DeLuca as a prior art in the same field of endeavor. DeLuca teaches an outside vapor deposition process comprising injecting glass fine particles generated with a burner for glass fine particle synthesis onto a starting material rotating around its central axis as an axis of rotation (col. 5 line 54 to col. 6 line 12, fig. 1). Accordingly, it would have been obvious to one of ordinary skill in the art at the time of the invention to have expected the outside vapor deposition process of Griece to comprise of injecting glass fine particles generated with a burner for glass fine particle synthesis onto a rotating starting material, as DeLuca teaches this is a typical method for producing an optical fiber preform. Grieco also teaches sintering the preform to vitrify it into transparent glass by suspending and heating the preform in a furnace core tube, while flowing a sintering gas in the furnace core tube ([0017], [0018]). Grieco further teaches flowing helium at a flow rate of 20 slpm to 40 slpm during sintering ([0016]) and provides examples using 25 slpm, 30 slpm, and 40 slpm of helium gas in table 1. Note, a sintering gas flow rate of 20 slpm is less than 21.0 L/min. Such flow rates in the furnace of Grieco having an inner diameter of 330 mm ([0188]) provides for a linear speed of the helium gas in the range of 0.234 m/min to 0.468 m/min (i.e. 0.234 m/min at 20 slpm, 0.292 m/min at 25 slpm, and 0.351 m/min at 30 slpm). Notes, all of these linear speeds are less than 0.57 m/min. Grieco further teaches the sintering is performed by lowering the preform into a heating zone of the furnace core tube at a rate in the range of 4 mm/min to 8 mm/min ([0115]), wherein the heating zone comprises an annular heater that surrounds a muffle tube ([0087]). However, Grieco doesn’t specify the length of the heating zone. Like Grieco, Lane teaches a conventional method for producing optical fiber preform comprising manufacturing a glass fine particle deposit (porous glass preform) by an outside vapor deposition process (col. 1 lines 14-16), and sintering the soot preform to vitrify it into transparent glass by suspending and heating the glass fine particle deposit in a furnace core tube, while flowing a sintering gas comprising helium in the furnace core tube (col. 1 lines 21-40, 48-53). Lane further teaches the sintering is performed by lowering the preform into a heating zone of the furnace core tube at a rate of 5 mm/min, the zone having a height of 26cm (col. 1 lines 34-37, 48-50). Like Grieco, Lane teaches the heating zone comprises an annular heater surrounding a muffle tube (col. 1 lines 34-38). Accordingly, it would have been obvious to one of ordinary skill in the art at the time of the invention to have tried a similar annular heating element having a height of 26 cm for the sintering of the preform in the method of Grieco as Lane teaches it is a size used in a conventional zone sintering furnace, with a reasonable expectation of success. In applying a heating zone length of 26 cm to the process of Grieco, the heating time period in the heating zone with a lowering rate of 4mm/min to 8mm/min is in the range of 65-32.5 mins, which provides for product of the time period and a linear speed in the range of 7.61 (m) to 30.4 (m) calculated respectively from 0.234m/minx65 mins and 0.468 m/minx32.5mins. Note, the range for the calculated product is 7.61 (m) to 30.4 (m), which significantly overlaps with the claimed range of 13.6 (m) to 18.1 (m) and 15.5 (m) to 34.1 (m).
Regarding claims 2-3, 6, 14-15 and 18, as discussed above, Grieco teaches a lowering rate of 4-8 mm/min, which provides for a heating time period in the range of 65-32.5 mins using the heating zone length of Lane, and the calculate product range is 7.61 (m) to 30.4 (m), which overlaps with the claimed range of 15.5 m to 18.1 m (claim 2), of 17.6 m to 18.1 m (claim 3), includes the value of 18.1 m (claim 6), of 17.6 m or more (claim 14), of 21.7 m or more (claim 15), and of 15.5 m to 34.1 m (claim 18).
Regarding claims 4 and 16, Grieco and Lane teach sintering of the soot preform to vitrify it into transparent glass comprises heating the soot preform by lowering the preform through a heating zone in the furnace core tube ([0007] and [0116], col. 1 lines 47-52, respectively).
Regarding claims 5 and 17, Grieco teaches supplying helium gas as sintering gas ([0016], [0188]).
Regarding claims 7 and 19, as described above, Grieco teaches the time period is calculated to be in the range of 65-32.5 mins, which includes values that are equal to or less than 60 mins.
Regarding claims 8 and 20, as discussed above, Grieco teaches the linear speed of the sintering gas flowing in the furnace core tube is calculated to be in the range of 0.234 m/min to 0.468 m/min, which include values that are greater than 0.36 m/min.
Regarding claims 9 and 21, Grieco teaches sintering temperatures can be set in the range of 1450°C to 1600°C ([0116]), which overlaps with the claimed range of 1555°C -1605°C.
Response to Arguments
Applicant’s arguments, filed July 3, 2026, with respect to the rejection(s) of claim 13 under Kanamori have been fully considered and are persuasive. Therefore, the rejection has been withdrawn. However, upon further consideration, a new ground(s) of rejection is made in view of Grieco, Lane and DeLuca.
Regarding Grieco, applicant references [0189] and argues Grieco teaches the flow rate is preferably higher than 25 L/min. This is not found persuasive as the teaching was in referenced to apparatus A, which was lacking in the improvement of apparatus B which included a flow control assembly. In other words, the unsatisfactory result is not due to the flow rate of the helium flow, but because of the apparatus assembly. In fact, Grieco emphasizes a desired to use less helium for cost reduction ([0016]).
Regarding the written description requirement, applicant argues the claimed feature of at least 13.6 m is supported. While a singular example of a non-preferred embodiment is disclosed in the table resulting in a product of 13.6, the specification is clearly directed to an invention wherein the helium gas flow is characterized by a product of time period and linear speed of at least 15.5 m or more. The objective of the invention, as clearly disclosed in the specification, is on reducing unmelted areas in the glass, and in order to achieve this objective, a lower limit for a product of the He linear speed and a time period for heating is set to 15.5 m. Accordingly, the specification does not offer support for the range between 13.6 m and 15.5 m.
Conclusion
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/QUEENIE S DEHGHAN/Primary Examiner, Art Unit 1741
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