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 .
Election/Restrictions
Claims 16-30 withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to nonelected inventions, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on July 14, 2026.
Applicant’s election without traverse of claims 1-15 in the reply filed on July 14, 2026 is acknowledged.
Priority
Acknowledgment is made of applicant’s claim for priority to US PROV63/302716 and CON PCT/US2023/061282 filed January 25, 2022 and January 25, 2023, respectively. The amended application data sheet of February 26, 2024 contradicts priority status as no parent cases are listed compared to the original application data sheet of January 4, 2024.
The contents of US PROV63/302716 do not lend support to currently presented claims 1-15 of the instant application. US PROV63/302716 mentions an excitation fluence applied (paragraph [0042]) but not an illumination fluence nor discloses providing a fluence “to effect a persistent reduction in blue-shift” in the quantum dot’s emission spectrum. Thus, once priority is granted to the continuation in part of PCT/US2023/061282, claims will receive an effective filing date of January 25, 2023. It is suggested that a correct application data sheet be filed.
Specification
The lengthy specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification.
The disclosure is objected to because of the following informalities: paragraphs listing references cited are unnecessary to include when those references are already included as part of the IDS. It is recommended to remove those paragraphs.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 6-9 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
The reasons for indefiniteness are applicable to claims 6-9 for the following reasons. Claim 6 directs towards a “higher-energy” and “lower-energy” emission of the quantum dot. Claims 7 and 8 also direct towards “lower-energy” lasing thresholds, in addition to the “higher-energy” and “lower-energy” emission by virtue of dependency on dependent claim 6. Claim 9 directs towards a “higher-energy” emission of the quantum dot, in addition to the “higher-energy” and “lower-energy” emission by virtue of dependency on dependent claim 6. The terms “higher -energy”, “lower-energy” are relative terms which render the claims indefinite. The terms are not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention.
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, 4, 10, 11 and 13-14 are rejected under 35 U.S.C. 103 as being unpatentable over Sum et al (US PGPub 20240271037).
Regarding claim 1, Sum teaches providing a quantum dot (CdSe/ZnS) in paragraphs [0054] and [0176] which are subjected to photon (illumination) fluences (Fig. 14). Sum does not disclose a resulting CIE or chromaticity index following the fluence application. In subsequent examples (data represented in Figs. 10 and 15-16), Sum also applies their method on perovskites but broadly teaches that their method can be applied to fluorescent based nanoparticles which suffer from maintaining stability in ambient conditions such as water, oxygen, heat or irradiation and is thus analogous in motivation to the invention as claimed. In paragraph [0164], Sum discloses that after irradiation by light (illumination fluence), the tested perovskites maintain invariant chromaticity (Fig. 10c-e), thus representing a crucial parameter to maintain over time. Maintaining chromaticity means the color emission maintains and thus would not blue-shift over time. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to apply the illumination fluence method of Sum to applicable nanoparticles outside of perovskites to ensure stable chromaticity and thus a reduction in blue-shifting over time and arrive at the invention as claimed. Thus, Sum teaches the claimed “A method for stabilizing a quantum dot's emission spectrum, comprising: illuminating the quantum dot with an illumination fluence sufficient to effect a persistent reduction in blue-shift over time in the quantum dot's spectrum”.
Regarding claim 4, Sum teaches the method of claim 1. Sum teaches providing a core-shell quantum dot (CdSe/ZnS) in paragraphs [0054] and [0176] which are subjected to photon (illumination) fluences (Fig. 14). Thus, Sum teaches the claimed “The method of claim 1, wherein a quantum dot comprises a core-shell quantum dot”.
Regarding claim 10, Sum teaches the method of claim 1. Sum excites using a 400nm wavelength which falls into the range as claimed of 400-600nm. Thus, Sum teaches the claimed “The method of claim 1, wherein the illumination is in the range of from about 400 to 600 nm, the illumination optionally being in the range of from about 480 to about 520 nm, the illumination optionally being at a wavelength of 488 nm”.
Regarding claim 11, Sum teaches the method of claim 1. In the background motivation, Sum discusses the limitations of current nanoparticle technology whereby most nanoparticles deteriorate in terms of photoluminescent properties naturally over time due to poor ambient stability. Sum discloses that their method aids in enhancing stability through exposure to an illumination fluence and whereby the exposed particles maintain PLQY and chromaticity, factors pertaining to spectral stability. Although Sum characterizes in detail more relevant to perovskites, Sum applies the same process to quantum dots and thus would be expected to hold such parameters compared to quantum dots not exposed to illumination. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to test untreated quantum dots compared to treated quantum dots to ensure that the treated quantum dots display superior stability compared to a reference untreated quantum dot as applied to the disclosed perovskites of Sum and arrive at the invention as claimed. Thus, Sum teaches the claimed “The method of claim 1, wherein following the illuminating, the quantum dot exhibits a greater spectral stability over a period of time than a comparable quantum dot free of the illuminating over the period of time”.
Regarding claim 13, Sum teaches the method of claim 11. Sum shows that the perovskites tested show invariant chromaticity, thus no spectral shift or perhaps minimal shift that is undetected in the emission. Therefore, it would be expected that the spectral shift is less than about 2.5 meV over a time of operation. From Fig. 10, Sum exposes the perovskites to an illumination fluence for 0, 6, 12, 18, and 24 hours with invariant chromaticity change. Thus, it would also be expected that 15 minutes of operation would also exhibit a spectral shift less than 2.5 meV if hours of exposure do not shift the spectra. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to ensure the same characteristics holdover when applying such a process to quantum dots as a known alternative nanoparticle capable of undergoing the method of Sum and arrive at the invention as claimed. Thus, Sum teaches the claimed “The method of claim 11, wherein following the illuminating, the quantum dot exhibits a spectral shift of less than about 2.5 meV over about 15 minutes of continuous operation”.
Regarding claim 14, Sum teaches the method of claim 11. Sum shows that the perovskites tested show invariant chromaticity, thus no spectral shift or perhaps minimal shift that is undetected in the emission. Therefore, it would be expected that the spectral shift is between 0.5-2.5 meV over a time of operation. From Fig. 10, Sum exposes the perovskites to an illumination fluence for 0, 6, 12, 18, and 24 hours with invariant chromaticity change. Thus, it would also be expected that 15 minutes of operation would also exhibit a spectral shift between 0.5-2.5 meV if hours of exposure do not shift the spectra. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to ensure the same characteristics holdover when applying such a process to quantum dots as a known alternative nanoparticle capable of undergoing the method of Sum and arrive at the invention as claimed. Thus, Sum teaches the claimed “The method of claim 11, wherein following the illuminating, the quantum dot exhibits a spectral shift of from about 0.5 to about 2.5 meV over about 15 minutes of continuous operation”.
Claims 2, 3, and 5 are rejected under 35 U.S.C. 103 as being unpatentable over Sum et al as applied to claim 1 above, and further in view of Cao et al (US PGPub 20110150938).
Sum teaches the method of claim 1 but does not specify including quantum dots as a plurality contained in a superparticle. Cao teaches the preparation of superparticles which are created through the self-assembly of quantum dots or nanoparticles in colloidal synthesis. Superparticles described by Cao (paragraphs [0003-7] and [0008-16]) are advantageous due to the ability of efficient control of size- and shape-distributions and long-range ordering. Furthermore, superparticles comprising fluorescent nanoparticles such as quantum dots can be utilized in light emitting diodes. In paragraph [0016], Cao discloses superparticles comprising cadmium selenide quantum dots (Figs. 5, 14, 16, and 19 and Examples 2, 9-12). CdSe quantum dots are the same dots provided by Sum, so the assembly by Cao could be readily applied in the fluence method of Sum. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to substitute for the CdSe quantum dots provided by Sum the superparticle assembly of CdSe quantum dots, as informed by Cao, as superparticles provide more advantageous properties to quantum dots alone with efficient control of size- and shape-distributions and arrive at the invention as claimed. Thus, Sum and Cao teach the claimed “The method of claim 1, wherein the quantum dot is comprised in a superparticle that comprises plurality of quantum dots”.
Regarding claim 3, Sum and Cao teach the method of claim 2. Neither Sum nor Cao provide an example of multiple types of quantum dots emitting different colors. However, Cao teaches in paragraph [0104] that nanoparticles (quantum dots) can include more than one such nanoparticle or a type of nanoparticle. Further, Cao teaches that such superparticles are commonly implemented in light emitting devices. It is commonly known and utilized in the art that multiple nanoparticles emitting different wavelengths or colors of light can be employed in light emitting devices such that the combination of colors can produce one color such as white light (when combining red, green, and blue emission). It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to include multiple types of nanoparticles in the superparticle of Cao such that multiple colors are emitted to produce one color such as white light in a light emitting device and arrive at the invention as claimed. Thus, Sum and Cao teach the claimed “The method of claim 2, wherein a first quantum dot of the plurality of quantum dots emits in a first color and wherein a second quantum dot of the plurality of quantum dots emits in a second color.”.
Regarding claim 5, Sum and Cao teach the method of claim 2. In paragraphs [0041] and [0048], Cao teaches that the nanoparticles can be provided with surface ligands (thus, ligand-bearing) which can influence superparticle lattice spacing and formation of nanoparticle-micelles via hydrophobic van der Waals interactions (paragraphs [0052-53]). Cao also teaches in claim 49 that the superparticle is synthesized by mixing a first solution comprising ligand-functionalized nanoparticles. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to provide quantum dots having surface ligands in order to influence superparticle lattice spacing and the formation or assembly of nanoparticle micelles into a superparticle and arrive at the invention as claimed. Thus, Sum and Cao teach the claimed “The method of claim 2, wherein the quantum dot is a ligand-bearing quantum dot”.
Claims 6-9 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Sum et al as applied to claim 1 above, and further in view of le Feber et al (NPL "Colloidal-quantum-dot ring lasers with active color control").
Regarding claim 6, Sum teaches the method of claim 1. Sum does apply increasing fluences to a quantum dot and to the perovskites but does not specify higher-energy emissions surpassing a lower-energy emission. Le Feber also applies fluences through a lasing threshold technique to CdSe-based quantum dots whereby Le Feber gradually increases the fluence from 30uJ/cm2 to >250 uJ/cm2 whereby the color emission from excitons in the shell changes from red to green. Red wavelengths are longer in length compared to green wavelengths. Since wavelength and energy are inversely related, red emission would be considered a lower-energy emission compared to green wavelength emission. Furthermore, Le Feber discloses that the color switching occurs due to a competition between exciton localization into the core and stimulated emission from excitons in the shell. In the second column of pg 1031 and Fig. 5, Le Feber teaches that at lower excitation powers, red lasing emission occurs. At medium exciton powers, there is an orange color indicating a mixing of green and red emissions before the green stimulated emission is able to outpace the excitons responsible for red emission. At the higher excitation powers >200uJ/cm2, green lasing emerges. Le Feber teaches that such color switching quantum dots enables controlled radiative and nonradiative rates, as well as fast color-switchable or white-light lasers which can drive novel techniques for biological and chemical sensing, laser imaging and displays, and wavelength-division multiplexing. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to apply quantum dots of Le Feber into the fluence method of Sum such that color switching can occur enabling controlled radiative and nonradiative rates and fast color-switchable lasers and arrive at the invention as claimed. Thus, Sum and Le Feber teach the claimed “The method of claim 1, wherein a fluence of the illumination is increased to an illumination level at which higher-energy emission of the quantum dot surpasses lower- energy emission of the quantum dot.”.
Regarding claim 7, Sum and Le Feber teach the method of claim 6. The quantum dots characterized by Le Feber, as described in the rejection and arrival to claim 6 above, exhibit different energy lasing thresholds resulting in different color emissions. Le Feber gradually increases the fluence energy whereby the illumination level exceeds a lower-energy lasing threshold when color emission switches from red to green. Thus, Sum and Le Feber teach the claimed “The method of claim 6, wherein the quantum dot has a lower-energy lasing threshold, and wherein the illumination level exceeds the lower-energy lasing threshold”.
Regarding claim 8, Sum and Le Feber teach the method of claim 7. In Fig. 3dii vs 3diii, Le Feber applies 74uJ/cm2 to reach red lasing and then applies 260uJ/cm2 to achieve orange lasing. 260 is about 4-6 times greater than 74 (260/74 = 3.5). Additionally, Le Feber teaches that green lasing emerges for all radii at an excitation of 400uJ/cm2 which is 5.4 times greater than 74uJ/cm2. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to apply an illumination level in a range of about 4 to 6 times greater than the lower-energy lasing threshold to achieve orange or green color emission from the quantum dot as informed by Le Feber and arrive at the invention as claimed. Thus, Sum and Le Feber teach the claimed “The method of claim 7, wherein the illumination level is from about 4 to about 6 times the lower-energy lasing threshold”.
Regarding claim 9, Sum and Le Feber teach the method of claim 6. Le Feber shows in Fig. 4 the resulting counts of green and red emission as a function of increasing fluence applied to different radii quantum dots. The plots cut off for most radii before the green emission or higher-energy emission starts to diminish but the shape of the curve suggest that such emission will diminish past a certain fluence level. For a radius of 2.5µm, the green emission does diminish around a fluence ~700-800uJ/cm2. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to continue increasing fluence such that green emission diminishes if the color is no longer desired and arrive at the invention as claimed. Thus, Sum and Le Feber teach the claimed “The method of claim 6, further comprising increasing the fluence of the illumination until higher-energy emission of the quantum dot diminishes”.
Regarding claim 12, Sum teaches the method of claim 1 but does not report a Q factor. Le Feber discloses Q factors after fluence treatment in Fig. 2b whereby quantum dots of radius ≤ 3µm show tightly contained Q factors while dots of radius ≥4µm exhibit a much larger spread. Le Feber teaches that the quality factor or Q factor quantifies losses in resonators. The sharper features of spectra in Fig. 2a from which Q factors are obtained represent leakage or scattering of photons from cavity modes. Thus, a lower Q factor would be desirable and consistency in such a Q factor after fluence would be preferred so that utilized quantum dots remain stable over time. It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to utilize quantum dots of radius ≤ 3µm such that the Q factor remains constricted in order to minimize scattering, leakage, or losses in the resonator and arrive at the invention as claimed. Thus, Sum and Le Feber teach the claimed “The method of claim 1, wherein the quantum dot exhibits a Q factor within about 10% of the Q factor of a comparable quantum dot free of the illuminating”.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Sum et al as applied to claim 1 above, and further in view of McLaughlin et al (US PGPub 20170229619).
Sum teaches the method of claim 1. Sum does not disclose stability between quantum dots that were treated with a fluence vs untreated quantum dots but does show such stability in provided perovskites. McLaughlin also treats quantum dots with a fluence under a blue LED and shows that treated quantum dots remain more stable in PLQY or photoluminescence quantum yield (Fig. 11) compared to untreated quantum dots (controls – powders not brightened) which exhibit more volatility in average PLQY. McLaughlin treats the quantum dots while in dry powder stage and maintains the same QY in the polymer slurry as in LED device operation (paragraph [0088]). It would have been prima facie obvious to one of ordinary skill in the art, as of the effective filing date, to treat the quantum dots with a fluence while in the dry powder stage prior to ensure a more stable PLQY when implemented into an LED and arrive at the invention as claimed. Thus, Sum and McLaughlin teach the claimed “The method of claim 1, wherein following the illuminating, the quantum dot exhibits a greater spectral stability over a period of time than a comparable quantum dot free of the illuminating over the period of time”.
Allowable Subject Matter
Claim 15 is objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
The following is a statement of reasons for the indication of allowable subject matter: the art does not suggest nor teach providing two quantum dots that normally overlap in spectra but would no longer overlap after providing a specific illumination fluence. Le Feber teaches color switching of quantum dots but providing a fluence to the color switching threshold of two separate quantum dots (i.e., one core only dot and one core/shell dot) would still have overlap within a fluence level whereby both quantum dots emit light.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Watts et al (NPL "Light soaking in metal halide perovskites..." and Jung et al (NPL "Two-band optical gain and ultrabright electroluminescence...") discuss strategies towards influencing .
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/NWFG/Examiner, Art Unit 1759
/MELVIN C. MAYES/Supervisory Patent Examiner, Art Unit 1759
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