DETAILED ACTION
Response to Amendment
A Reply was filed 25 June 2026. All amendments therein have been entered. Claims 1-53 are pending. The subject matter of claim 2 is not shown in Figure 1. Thus, claims 2, 5-9, 14, and 22-53 are withdrawn. Claims 1, 3-4, 10-13, and 15-21 are further considered herein.
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claim Rejections - 35 USC § 112(b)
Claims 1, 3-4, 10-13, and 15-21 are rejected under 35 U.S.C. 112(b) as being indefinite for failing to particularly point out and distinctly claim the subject matter which an inventor regards as the invention.
Claim 1
The use of “second outer region” without mention of a “first outer region” is confusing and unclear. The use of “second outer region” implies that there is a “first outer region” in the same claim. However, claim 1 lacks mention of a “first outer region”. Thus, the claim appears to be incomplete.
The phrase “a second ignition temperature or energy that is higher than the first ignition temperature or energy of the first fuel material region” is unclear. The claim defines the first and second fuel material regions by reference to their relative "ignition temperature". However, the term "ignition temperature" is uncertain and unclear. It is noted that the ignition temperature of a fuel is not a single intrinsic material property, unlike, for example, a melting point. Rather, it is being viewed as corresponding to the temperature at which the energy generated by fusion reactions becomes sufficient to sustain the plasma without continued external heating. Consequently, the ignition temperature depends on a number of operating parameters, including temperature, choice of fuel, plasma density, confinement time, radiation losses, impurity levels, and plasma composition. Therefore, it cannot be regarded as a unique value characterizing the fuel itself. Hence, the claim is unclear.
Also, as best understood, the list of possible materials for the first and second fuel material regions can overlap. For example, it appears that both the first and second fuel material regions may include DLi6 or DLi7. In such embodiments, the requirement that the second fuel material region has a higher ignition temperature than the first fuel material region is not necessarily met. Therefore, the claim appears to cover embodiments which are inconsistent with one of its own limiting features.
Claim 19
In line 4, the phrase “a pulse width within a first of 1ns 40ns” is unclear. It is unclear whether the phrase should be interpreted as “a pulse width within a range of 1ns to 40ns”.
Review
The claims do not allow the public to be sufficiently informed of what would constitute infringement. Any claim not specifically addressed is rejected based upon its dependency.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1 and 3 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Barroso ("A numerical solution of the time-dependent neutron transport equation using the characteristic method. Applications to ICF and to hybrid fission-fusion systems", arXiv preprint arXiv:1704.02861 (2017)).
Barroso teaches a fuel target device comprising a center region comprising a first fuel material (LiDT), and a second outer region comprising a second fuel material (LiD). Particularly note Figure 15. Applicant’s specification acknowledges that DTLi and DLi are a solid at room temperature.
Claim Rejections - 35 USC § 103
Claims 1, 3, and 15-16 are rejected under 35 U.S.C. 103 as being unpatentable over Hunter (US 2020/0263981) in combination with Li (“Prediction of superionic state in LiH2 at conditions enroute to nuclear fusion”, Chinese Physics B, 32(10), (2023 Oct) 106103).
Claims 1 and 3
Hunter teaches [0043] a fuel target device comprising a center region (202) comprising a first fuel material (e.g., lithium deuteride), and a second outer region (206) comprising a second fuel material (e.g., pure deuterium). The fuel regions (202, 206) may be filled with different types of fusion fuel, such as: deuterium and tritium (DT), pure deuterium, lithium deuteride, lithium tritide, or any other fusion fuel or combination of fuels [0043].
Li shows that it is well known in the art to use solid lithium tritium-deuteride (LiTD) instead of lithium deuteride in order to improve fuel efficiency. Particularly note the Introduction section on page 1 at the first column. Applicant’s specification acknowledges that DTLi and DLi are a solid at room temperature. Also, handling is simplified since no cryogenic storage is required.
Thus, modification of Hunter to have employed the center region with fuel in the form of solid LiTD to have enhanced fuel efficiency and handling, as suggested by Li, would have been obvious to one of ordinary skill in the art. The result of the modification would have been predictable to the skilled artisan.
Claims 15-16
Hunter’s device is structurally capable of being used with a laser light source.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Hunter (US 2020/0263981) in combination with Li as applied to claim 1 above, and further in view of Piera ("A Physics of Inertial Fusion - Chapter III - Ignition and Implosion Hydrodynamics - An Assessment of Proton-Boron 11 Fusion in ICF Targets Triggered by DT Sparks", Fusion Science and Technology 1 (2004): 85-87).
It is well known in the art to use the center fuel region as a low-temperature "spark plug" or ignition core, where subsequent outward fuel regions require progressively higher temperatures to fully burn. For example, Piera shows using an inner fuel region as a spark for an outer fuel region of pB. Thus, modification of Hunter to have employed an outer fuel region of pB for a longer burn would have been obvious to one of ordinary skill in the art. The result of the modification would have been predictable to the skilled artisan.
Claims 10-13 and 17-19 are rejected under 35 U.S.C. 103 as being unpatentable over Hunter (US 2020/0263981) in combination with Li as applied to claim 1 above, and further in view of Stephens ("Implosion hydrodynamics of fast ignition targets", Physics of Plasmas 12, no. 5 (2005)).
Hunter’s device is structurally capable of being used with a laser light source.
Stephens shows (e.g., Figure 1) that it is conventional in the art to use a cone-shaped groove or metal cone that is coated with gold (Au) or lead (Pb), which allows a laser to ignite the fuel. Modification of Hunter to have employed a conventional cone to allow for fuel ignition, as suggested by Stephens, would have been obvious to one of ordinary skill in the art. The modification result would have been predictable to a skilled artisan.
Claims 20-21 are rejected under 35 U.S.C. 103 as being unpatentable over Hunter (US 2020/0263981) in combination with Li as applied to claim 1 above, and further in view Hunter (WO 2011/146113).
Hunter (WO) shows that it is well known in the art to use a target having a sphere shape or a cylindrical shape. The target has a diameter of 1 mm - 9 mm (e.g., page 14, last paragraph; page 16, fourth paragraph). Modification of Hunter (US) to have employed the target with a conventional sphere or cylindrical shape, as suggested by Hunter (WO), would have been obvious to one of ordinary skill in the art. The result of the modification would have been predictable to the skilled artisan.
Objection to the Abstract
The Abstract is objected to because the term "ignition temperature" is unclear, as discussed above.
The Abstract is also objected to because it includes an unclear long rambling sentence. It is unclear where one feature ends and another feature begins. It is suggested that the long rambling sentence be broken into several shorter clear sentences.
An Abstract should include that which is new in the art to which the recited invention pertains. Correction is required. See MPEP § 608.01(b).
Response to Arguments
Applicant's arguments have been fully considered but they are not persuasive.
Applicant argues different ignition temperatures. However, this claim terminology is unclear, as discussed above. It is noted that this same issue was in corresponding EP application 24211165 (e.g., Action dated 26 June 2026). Regardless, the above prior art rejections meet the recited fuel material regions.
Applicant argues that Barroso is merely theoretical. Applicant has not addressed why their invention is not merely theoretical. Nevertheless, this argument is immaterial because the thrust of Barroso’s disclosure is usable by the skilled artisan.
Additional Comments
Upon cursory review:
withdrawn claim 23 has the phrase “to irradiated” (line 6), which may be unclear and incomplete.
the subject matter of withdrawn claim 2 may be absent (not shown) in the Figures.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. Prosecution on the merits is closed. 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 will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
RCE Eligibility
Since prosecution is closed, this application is now eligible for a request for continued examination (RCE) under 37 CFR 1.114. Filing an RCE helps to ensure entry of an amendment to the claims and/or the specification.
Contact Information
Examiner Daniel Wasil can be reached at (571) 272-4654, on Monday-Thursday from 10:00-4:00 EST. Supervisor Jack Keith (SPE) can be reached at (571) 272-6878.
/DANIEL WASIL/
Examiner, Art Unit 3646
Reg. No. 45,303
/JACK W KEITH/Supervisory Patent Examiner, Art Unit 3646
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