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 .
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 12/04/2023 and 11/13/2024 was being considered by the examiner.
Election/Restrictions
A restriction requirement was made between Group I, claims 1-9, directed to a radiation detector, and Group II, claims 10-20, directed to a method of preparing a perovskite thick film. Applicant elected Group I, claims 1-9, without traverse. Accordingly, this action examines claims 1-9 only. Claims 10-20 remain withdrawn from consideration.
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.
Claim(s) 1 – 6 and 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al. (“CMOS Based High-Resolution Dynamic X-Ray Imaging with Inorganic Perovskite,” arXiv:2210.02073, posted Oct. 5, 2022) in view of Wang et al. (“Ultra-stable CsPbBr3 Perovskite Nanosheets for X-Ray Imaging Screen,” Nano-Micro Letters 11:52 (2019)) and Huang et al. (US 2020/0028022 A1).
With regard to claim 1, Liu teaches a direct-conversion X-ray detector fabricated with a 300 μm inorganic CsPbBr3 thick film printed directly on a tailored 72×72-pixel CMOS sensor array. Liu explains that X-ray-generated electrons drift toward CMOS pixel collection electrodes and describes multifunctional amplifier and leakage-current-compensation circuitry integrated in the CMOS array. Liu therefore teaches the substrate/CMOS support, pixel array, thick CsPbBr3 radiation-sensitive film formed on the pixel array, and electrically connected pixel readout circuitry (Liu, Abstract; pp. 3-6; Figs. 1-2).
Liu does not expressly teach that the 300 μm film has nanosheet structure or that the completed film comprises both a surfactant and a ligand.
Wang teaches CsPbBr3 nanosheets, a self-assembled crack-free nanosheet film used as an X-ray imaging screen, and synthesis using octylamine and octanoic acid. Wang further identifies ligand coverage of the nanosheets and demonstrates X-ray-excited radioluminescence (Wang, pp. 2-6; Figs. 1-5).
Huang teaches adding a small amount of surfactant to a perovskite ink before coating to improve wetting, coverage, smoothness, and film continuity. Huang expressly identifies Tween 60, permits cesium and formamidinium lead-halide perovskites, and lists spray coating among suitable scalable coating processes (Huang, [0014], [0052]-[0055], [0069], [0071]; Figs. 5, 13, 15, 20).
It would have been obvious to employ Wang’s known CsPbBr3 nanosheet/ligand material as the radiation-responsive perovskite layer on Liu’s pixelated CMOS detector and to include Huang’s known surfactant additive during coating. The references address complementary parts of the same recognized engineering problem: obtaining a uniform, low-defect, radiation-responsive perovskite layer on an electronic readout substrate. Wang supplies the known X-ray-responsive nanosheet morphology and ligand chemistry, while Huang supplies the predictable wetting and coverage improvement for coating the material over the array.
With regards to claim 2, Liu modified discloses the claimed invention according to claim 1, but fails to expressly disclose a surfactant selected from Tween 20, Tween 40, Tween 60, Tween 65, and Tween 80.
Huang expressly identifies polyethylene glycol sorbitan monostearate (Tween 60) as a nonionic surfactant used in perovskite films and reports device testing with Tween 60 (Huang, [0014], [0054], [0069], [0071], [0078]; Figs. 5, 13, 15). Disclosure of one member of the recited alternatives satisfies this limitation.
In view of the utility, to include Tween 60 in order to enhance the detection as needed, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to modify Liu to include the teachings such as that taught by Huang.
With regards to claim 3, Liu modified discloses the claimed invention according to claim 1, but fails to expressly disclose 0.005 wt% to 0.05 wt% Tween 60.
Huang discloses low surfactant concentrations, including 0.01-1 mM and a 0.25 mM test concentration, and identifies surfactant concentration as adjustable for the material and application (Huang, [0010], [0053], [0069], [0078], [0080]). A 0.25 mM Tween 60 solution is approximately 0.033 wt% on a conventional dilute-solution mass basis and therefore lies within the claimed interval. Independently, concentration was a known result-effective variable for balancing wetting and film quality against excess organic additive.
In view of the utility, to include Tween 60 in order to enhance the detection as needed, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to modify Liu to include the teachings such as that taught by Huang.
With regards to claim 4, Liu modified discloses the claimed invention according to claim 1, but fails to expressly disclose octylamine with octanoic acid, or decylamine with decanoic acid.
Wang expressly uses octylamine and octanoic acid in forming CsPbBr3 nanosheets and identifies ligand coverage of the nanosheets (Wang, p. 2; pp. 4-5; Figs. 1(a), 3(c)). Employing the exact octylamine/octanoic-acid pair used by Wang would predictably form and stabilize Wang’s known nanosheet morphology in the modified Liu detector.
In view of the utility, to include Tween 60 in order to enhance the detection as needed, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to modify Liu to include the teachings such as that taught by Huang.
With regards to claim 5, Liu modified discloses the claimed invention according to claim 1, but fails to expressly disclose low-angle XRD signals at 3.9±0.3°, 7.6±0.3°, and 11.4±0.3°.
Wang reports corresponding low-angle signals at 3.9°, 7.9°, and 11.8° for the layered CsPbBr3 nanosheet assembly (Wang, p. 5). The first two values fall within the claimed intervals, and the third differs from the upper claimed boundary by only 0.1°. The prior-art and claimed peaks characterize the same ordered nanosheet material and the same sequence of low-angle reflections.
Notice where a claimed numerical value is sufficiently close to the prior-art value and concerns the same recognized property, a prima facie case of obviousness exists absent evidence that the narrow difference is critical or produces an unexpected result.
It would therefore have been obvious to obtain or select the recited peak positions through ordinary control of nanosheet spacing, sample preparation, strain, substrate, and measurement conditions. No criticality is apparent at 11.7° versus 11.8° on the present record.
With regards to claim 6, Liu modified discloses the claimed invention according to claim 1, and further Liu expressly discloses a 300 μm CsPbBr3 film printed on the CMOS array, within the claimed interval, and explains that thickness can be adjusted from tens to hundreds of micrometers by repeating the printing procedure (Liu, Abstract; pp. 3-6; Figs. 1-2).
With regards to claim 8, Liu modified discloses the claimed invention according to claim 1, and further Liu expressly teaches and demonstrates a direct-conversion X-ray detector, and Wang expressly demonstrates an X-ray imaging screen (Liu, Abstract; pp. 3-6; Fig. 1; Wang, pp. 1-2, 6; Fig. 5). Disclosure of the X-ray alternative satisfies the claim.
In view of the utility, to include an x-ray alternative to enhance the detection or improve radiation capabilities as needed, as such, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to modify Liu to include the teachings such as that taught by Wang.
Claim(s) 7 and 9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Liu in view of Wang, Huang, and Chen et al. ("One-Step Spray Coating Strategy Toward a Highly Uniform Large-Area CsPbBr3@PMMA Composite Film for Backlit Display,” Optics Express 30(12), 2022).
With regards to claim 7, Liu modified discloses the claimed invention according to claim 1, but fails to expressly disclose a detecting-surface area of 200 cm² to 2500 cm².
Chen demonstrates ultrasonic spray deposition of a uniform 20 cm × 20 cm CsPbBr3 composite film, i.e., 400 cm², within the claimed interval (Chen, Abstract; p. 20243; Fig. 1).
Huang independently teaches scalable large-area perovskite coating and surfactant-assisted full coverage and smoothness (Huang, [0007]-[0008], [0052]-[0055], [0062]-[0064]).
As such, it would have been obvious to a person of ordinary skill in the art at the time the invention was made to scale the modified Liu detector layer to Chen’s demonstrated area when a larger imaging field was desired because Chen and Huang teach the needed scalable coating and uniformity.
With regards to claim 9, Liu modified discloses the claimed invention according to claim 1, but fails to expressly disclose a radioluminescence between 520 and 600 nm, a full width at half maximum of 25 nm or less, and resolution of elements at least 100 μm wide.
Wang expressly reports X-ray-excited radioluminescence shifting from 515 to 520 nm as nanosheet-film thickness increases and an X-ray image resolution of approximately 330 μm, thereby satisfying the claimed wavelength endpoint and the ability to resolve 100 μm-or-wider elements (Wang, p. 6; Fig. 5).
Chen reports CsPbBr3 emission centered near 520 nm with an approximately 22-23 nm FWHM (Chen, p. 20247). Although Chen’s linewidth measurement is under optical excitation, it concerns the same CsPbBr3 band-edge emissive transition and is below the claimed threshold. The claimed 25 nm ceiling is close to, and broader than, the known narrow emission linewidth.
Therefore, it would have been obvious to obtain a radioluminescence linewidth no greater than 25 nm by using the same low-defect CsPbBr3 nanosheet material and ordinary optimization of crystal uniformity and defect density, absent evidence that the RL/PL linewidth distinction produces a critical or unexpected threshold at 25 nm.
Conclusion
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/DJURA MALEVIC/Examiner, Art Unit 2884
/UZMA ALAM/Supervisory Patent Examiner, Art Unit 2884
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