DETAILED ACTION
National Stage Application
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 .
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 28 August 2025 has been entered.
Claim Interpretation
The specification (e.g., see “… metalens 8 is configured on the basis of the phase design of Fresnel lens, for example …” in paragraph 42) serves as a glossary (MPEP § 2111.01) for the claim term “metalenses”.
The specification (e.g., see “… when a thickness of the semiconductor region 12 in the Z-axis direction is defined as t, the predetermined distance D is less than t/2. From another point of view, the predetermined distance D is 0 μm or more and 3 μm or less …” in paragraph 59) serves as a glossary (MPEP § 2111.01) for the claim term “predetermined distance”.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 at the time any inventions covered therein were effectively filed 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 at the time a later invention was effectively filed 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.
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 of this title, 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) 1-3 and 5-9 is/are rejected under 35 U.S.C. 103 as being unpatentable over Intermite et al. (Fill-factor improvement of Si CMOS single-photon avalanche diode detector arrays by integration of diffractive microlens arrays, Optics Express Vol. 23, no. 26 (December 2015), pp. 33777-33791) in view of Weinberg et al. (US 2008/0156993) and Engelberg et al. (The advantages of metalenses over diffractive lenses, Nature Communications Vol. 11, Article 1991 (Published online: April 2020), 4 pages).
In regard to claim 1, Intermite et al. disclose a light detector comprising:
(a) a semiconductor light detection element having a plurality of light detection units disposed two-dimensionally and readout wirings (e.g., “… positron emission tomography … low-noise Si SPADs are now a commercially available technology and are preferred … Inevitably the in-pixel circuitry compromises the available proportion of detector photo-sensitive area, and we need to consider the issue of geometric fill-factor which is the ratio of photo-sensitive area to total pixel area. A reduction in fill-factor causes a further deterioration of the effective SPDE, since a larger fraction of incident photons cannot be detected …” in the first three section 1 paragraphs); and
(b) a plurality of metalenses disposed on a surface of the semiconductor light detection element (e.g., “… microlenses were fabricated using Fresnel-like grooves and the lens surface was approximated by a modulo 2π zone plate representation, resulting in a fill-factor of the available area of ~100% (i.e. no dead zone between microlenses) for a square pixel … four masks were then used in multilevel photolithography to generate the 16 phase levels … overall coupling efficiency is defined as the percentage of the incident light on the microlens being concentrated within a 30 μm diameter circle on a pre-determined plane which is placed a fixed distance from the microlens. In this case the plane is fixed as being the rear surface of the microlens substrate where the detector array will be positioned after integration … fiducials on both the detector and microlens arrays were first aligned, the appropriate bonding parameters were then configured, and the bonding sequence was initiated. After a post-bond visual inspection of the fiducial alignment using a microscope, the wire bonding of the electrical connections to the SPAD array was then carried out …” in the first three and last section 3 paragraphs),
wherein each of the plurality of light detection units has an avalanche photodiode including a first semiconductor region of a first conductivity type and a second semiconductor region of a second conductivity type, the second semiconductor region located on a side of the surface with respect to the first semiconductor region and forming a PN junction with the first semiconductor region (e.g., “… single-photon avalanche diode (SPAD) detectors … photodiode when operated in Geiger-mode …” in the second and third section 3 paragraphs), and
wherein the plurality of metalenses are disposed two-dimensionally to overlap the plurality of light detection units when seen in a direction intersecting with the surface, and converge light such that a convergence spot is located at a position which is within the first semiconductor region of each of the plurality of light detection units and which is separated by a predetermined distance from a boundary between the first semiconductor region and the second semiconductor region in the direction intersecting with the surface (e.g., “… designed with the focal length exactly equal to the thickness of the substrate, so that light parallel to the optic axis would be focussed at the plane of the back of the substrate, which is directly bonded onto the plane of the SPAD array … focal length in fused silica of 1.022 ± 0.014 mm … errors in the focal positions caused by fabrication errors …” in the last complete paragraph on pg. 33782, the first paragraph on pg. 33783, and the first paragraph on pg. 33789),
wherein, a wavelength of the light that generates electric charge within the first semiconductor region is defined as λ (μm) (e.g., see “… 500-900 nm …” in last section 1 paragraph that can also be labeled as λ (μm)), each of the plurality of metalenses has a numerical aperture of ((0.61)2πλ)1/2 or more (e.g., see “… thinner substrates will be used in future work to decrease the microlens f-numbers, by adapting the fabrication processes accordingly …” in the last section 6 paragraph or alternatively it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to provide “thinner substrates” for the microlens of Intermite et al., in order to achieve decreased “microlens f-numbers” (or increased numerical apertures such as ((0.61)2πλ)1/2 or more), and
wherein the plurality of metalenses are metasurface lenses formed of an inorganic substance (e.g., “… focal length in fused silica of 1.022 ± 0.014 mm …” in the first paragraph on pg. 33783).
The detector of Intermite et al. lacks an explicit description of details of the “… SPAD …” such as a quenching resistor including one end electrically connected to the second semiconductor region and another end electrically connected to the readout wiring and an explicit description of details of the “… microlens …” such as a thickness equal to or less than the wavelength λ (µm) of the light. However, “… SPAD …” details are known to one of ordinary skill in the art (e.g., see “… reverse-biasing the photodiode with a bias voltage Ebias … nearly uniform field of the depletion zone separates the electron-and-hole pair, causing the electron and hole to be driven towards the n+ and p sides, respectively. When the drifting electron reaches the pn junction, the electron experiences the high electric field and accelerates and collides with the silicon atomic structure, releasing additional electrons and holes via secondary ionization, known as an avalanche. Thus, from a single photon entering the pn junction, a large number of electrons and holes can be generated and contribute to a photocurrent represented in FIG. 13 by reference numeral 238. The photocurrent output, i.e., analog signals 238 of a plurality of sensor elements 212 is collected as a summed analog signal 252. FIG. 12 illustrates each sensor element 212 arranged in series with a respective quenching element 230 … quenching elements 230 are produced by complementary metal-oxide-semiconductor (CMOS)-compatible technology, preferably using poly-silicon (or alternatively silicon carbide) for reaching the high resistive values required for effective quenching …” in
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and paragraphs 132 and 136-137 of Weinberg et al.) and “… microlens …” details are known to one of ordinary skill in the art (e.g., see “… high-NA diffractive lenses were demonstrated more than a decade ago … Assuming a moderately high NA, say of 0.5, the smallest period of the diffractive lens turns out to be 2λ (λ being the central working wavelength of the lens). With 4 phase levels, providing efficiency of ∼70%13, the minimum feature size is 2λ/4 = λ/2 –i.e., it is subwavelength …” in the second paragraph on pg. 3 of Engelberg et al.). It should be noted that “when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable results”. KSR International Co. v. Teleflex Inc., 550 U.S. 398 at 416, 82 USPQ2d 1385 (2007) at 1395 (citing United States v. Adams, 383 U.S. 39, 40 [148 USPQ 479] (1966)). See MPEP § 2143. In this case, one of ordinary skill in the art could have substituted a known conventional SPAD (e.g., comprising details such as “quenching elements 230” electrically connected in series between “analog signal 252” and the diode’s anode of “sensor elements 212”, in order to achieve “high resistive values required for effective quenching”) for the unspecified SPAD of Intermite et al. and a known conventional microlens (e.g., comprising details such as “smallest period of the diffractive lens turns out to be 2λ (λ being the central working wavelength of the lens). With 4 phase levels, providing efficiency of ∼70%13, the minimum feature size is 2λ/4 = λ/2 –i.e., it is subwavelength”, in order to achieve “a moderately high NA”) for the microlens of Intermite et al. and the results of the substitution would have been predictable. Therefore it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to provide a known conventional SPAD (e.g., comprising details such as a quenching resistor including one end electrically connected to the second semiconductor region and another end electrically connected to the readout wiring) as the unspecified SPAD of Intermite et al. and to provide a known conventional microlens (e.g., comprising details such as a thickness equal to or less than the wavelength λ (µm) of the light) as the microlens of Intermite et al.
In regard to claim 2 which is dependent on claim 1, Intermite et al. also disclose “… photodiode …” (third section 3 paragraph). Thus a thickness of the photodiode’s first semiconductor region in the direction intersecting with the surface can be labeled as t. Further, a prima facie case of obviousness exists (MPEP § 2144.05) since the claimed predetermined distance range of less than t/2 lie inside the range disclosed by the cited prior art (e.g., “… designed with the focal length exactly equal to the thickness of the substrate, so that light parallel to the optic axis would be focussed at the plane of the back of the substrate, which is directly bonded onto the plane of the SPAD array … focal length in fused silica of 1.022 ± 0.014 mm … errors in the focal positions caused by fabrication errors …” in the last complete paragraph on pg. 33782, the first paragraph on pg. 33783, and the first paragraph on pg. 33789).
In regard to claims 3 and 5 which are dependent on claim 1, Intermite et al. also disclose that when a standard deviation of a Gaussian function in a case where a beam profile of the convergence spot in the direction intersecting with the surface is approximated to the Gaussian function is defined as σ (e.g., “… diffraction limited spot diameter (1/e2 width) …” in the first paragraph on pg. 33783 or alternatively it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention that the diffraction limited profile can be approximated by a Gaussian function). The detector of Intermite et al. lacks an explicit description of details of the “… SPAD …” such as the predetermined distance is ≥0 μm or ≥0σ and also ≤3 μm or ≤3σ. However, “… SPAD …” details are known to one of ordinary skill in the art (e.g., see “… from a single photon entering the pn junction, a large number of electrons and holes can be generated and contribute to a photocurrent …” in paragraphs 136-137 of Weinberg et al.). It should be noted that “when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable results”. KSR International Co. v. Teleflex Inc., 550 U.S. 398 at 416, 82 USPQ2d 1385 (2007) at 1395 (citing United States v. Adams, 383 U.S. 39, 40 [148 USPQ 479] (1966)). See MPEP § 2143. In this case, one of ordinary skill in the art could have substituted a known conventional SPAD (e.g., comprising details such as “a single photon entering the pn junction”, in order to achieve “a photocurrent”) for the unspecified SPAD of Intermite et al. and the results of the substitution would have been predictable. Therefore it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to provide a known conventional SPAD (e.g., comprising details such as the predetermined distance is ≥0 μm or ≥0σ and also ≤3 μm or ≤3σ) as the unspecified SPAD of Intermite et al.
In regard to claim 6 which is dependent on claim 1, Intermite et al. also disclose a light transmitting substrate provided with the plurality of metalenses, wherein the plurality of metalenses are disposed on the surface of the semiconductor light detection element via the light transmitting substrate (e.g., “… designed with the focal length exactly equal to the thickness of the substrate, so that light parallel to the optic axis would be focussed at the plane of the back of the substrate, which is directly bonded onto the plane of the SPAD array …” in the last complete paragraph on pg. 33782).
In regard to claim 7 which is dependent on claim 1, Intermite et al. also disclose that the semiconductor light detection element is electrically and physically connected to the wiring substrate (e.g., “… wire bonding of the electrical connections to the SPAD array was then carried out …” in the last section 3 paragraph). The detector of Intermite et al. lacks an explicit description of details of the “… SPAD …” such as a wiring substrate disposed on a side opposite to the plurality of metalenses with respect to the semiconductor light detection element. However, “… SPAD …” details are known to one of ordinary skill in the art (e.g., see “… Vias (e.g., traces that connect one side of the substrate to the other) are then etched in between the APDs and metal bridges patterned within the vias to connect each APD with the corresponding readout circuit. In an alternative embodiment, the readout CMOS chip is bonded to the other side of the APD array chip (i.e., the epitaxial side instead of the substrate side). In another alternative embodiment, the APD layer may be connected to the comparator layer in a three-dimensional structure (e.g., fabricated by 3-D CMOS). With such a three-dimensional structure, the sum of micro-pixels may be digitized, or comparators may be placed below each micro-pixel in order to form a direct digital signal that can be counted …” in and paragraph 100 of Weinberg et al.). It should be noted that “when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable results”. KSR International Co. v. Teleflex Inc., 550 U.S. 398 at 416, 82 USPQ2d 1385 (2007) at 1395 (citing United States v. Adams, 383 U.S. 39, 40 [148 USPQ 479] (1966)). See MPEP § 2143. In this case, one of ordinary skill in the art could have substituted a known conventional SPAD (e.g., comprising details such as “Vias for the “readout CMOS chip is bonded to the other side of the APD array chip”) for the unspecified SPAD of Intermite et al. and the results of the substitution would have been predictable. Therefore it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to provide a known conventional SPAD (e.g., comprising details such as a wiring substrate disposed on a side opposite to the plurality of metalenses with respect to the semiconductor light detection element) as the unspecified SPAD of Intermite et al.
In regard to claims 8 and 9, the cited prior art is applied as claim 1 above. Intermite et al. also disclose a PET device (e.g., “… positron emission tomography …” in the first section 1 paragraph). The device of Intermite et al. lacks an explicit description of details of the “… positron emission tomography …” such as a plurality of radiation detectors disposed in an annular shape, and wherein each of the plurality of radiation detectors comprises a scintillator disposed on the semiconductor light detection element. However, “… positron emission tomography …” details are known to one of ordinary skill in the art (e.g., see “… PET … annular configuration of units or banks 54 … Each bank 54 possesses one or more sub-modules, generally designated by reference numeral 68 in FIG. 2. As best shown in FIG. 3A, sub-module 68 includes a meta-array of scintillators 80 and photosensors 84 … Photosensors 84 may comprise, for example, high-gain avalanche photodiodes (also known as silicon photomultipliers) …” in and paragraphs 72-73 and 81 of Weinberg et al.). It should be noted that “when a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable results”. KSR International Co. v. Teleflex Inc., 550 U.S. 398 at 416, 82 USPQ2d 1385 (2007) at 1395 (citing United States v. Adams, 383 U.S. 39, 40 [148 USPQ 479] (1966)). See MPEP § 2143. In this case, one of ordinary skill in the art could have substituted a known conventional PET (e.g., comprising details such as “annular configuration of” “scintillators” and “avalanche photodiodes” , in order to achieve “PET”) for the unspecified PET of Intermite et al. and the results of the substitution would have been predictable. Therefore it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to provide a known conventional PET (e.g., comprising details such as a plurality of radiation detectors disposed in an annular shape, wherein each of the plurality of radiation detectors comprises the light detector and a light emitting body configured to emit light upon incidence of radiation, and wherein the light emitting body is disposed on a side opposite to the semiconductor light detection element with respect to the plurality of metalenses) as the unspecified PET of Intermite et al.
Response to Arguments
Applicant’s arguments with respect to the amended claims have been fully considered but are moot in view of the new ground(s) of rejection.
Conclusion
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/SL/
Examiner, Art Unit 2884
/DAVID J MAKIYA/Supervisory Patent Examiner, Art Unit 2884