PPG Industries Ohio, Inc.Download PDFPatent Trials and Appeals BoardJun 25, 202015152936 - (D) (P.T.A.B. Jun. 25, 2020) Copy Citation UNITED STATES PATENT AND TRADEMARK OFFICE UNITED STATES DEPARTMENT OF COMMERCE United States Patent and Trademark Office Address: COMMISSIONER FOR PATENTS P.O. Box 1450 Alexandria, Virginia 22313-1450 www.uspto.gov APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO. 15/152,936 05/12/2016 Maurizio Ballarino 13009278P1 4042 24959 7590 06/25/2020 PPG Industries, Inc. IP Law Group One PPG Place 39th Floor Pittsburgh, PA 15272 EXAMINER VETERE, ROBERT A ART UNIT PAPER NUMBER 1712 NOTIFICATION DATE DELIVERY MODE 06/25/2020 ELECTRONIC Please find below and/or attached an Office communication concerning this application or proceeding. The time period for reply, if any, is set in the attached communication. Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the following e-mail address(es): ipdocket@ppg.com PTOL-90A (Rev. 04/07) UNITED STATES PATENT AND TRADEMARK OFFICE ____________ BEFORE THE PATENT TRIAL AND APPEAL BOARD ____________ Ex parte MAURIZIO BALLARINO, FRANCESCA BRUNETTI, MICHELA CAGLIANI, GIORGIO CARDONE, ALDO DI CARLO, and GIUSEPPINA POLINO Appeal 2019-004682 Application 15/152,936 Technology Center 1700 ____________ Before JEFFREY R. SNAY, MICHAEL G. McMANUS, and MERRELL C. CASHION, JR., Administrative Patent Judges. McMANUS, Administrative Patent Judge. DECISION ON APPEAL Pursuant to 35 U.S.C. § 134(a), Appellant1 seeks review of the Examiner’s decision to reject claims 1, 3–12, and 14–22. We have jurisdiction under 35 U.S.C. § 6(b). We affirm. 1 We use the word “Appellant” to refer to “applicant” as defined in 37 C.F.R. § 1.42. Appellant identifies the real party in interest as PPG Industries Ohio, Inc. Appeal Brief dated Jan. 29, 2019 (“Appeal Br.”) 3. Appeal 2019-004682 Application 15/152,936 2 CLAIMED SUBJECT MATTER The present application generally relates to organic photovoltaic systems and processes for making such systems. Specification filed May 12, 2016 (“Spec.”) ¶ 3. The Specification teaches that when light of the appropriate frequency strikes a semiconducting organic polymer “delocalized π electrons are excited by the electromagnetic energy from the polymer molecule’s highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO).” Id. ¶ 4. The Specification further teaches that “[t]he effectiveness and efficiency of organic photovoltaic systems at generating electricity depends in part on the ability of the systems to extract the excited and dissociated electrons from the photoelectric active material.” Id. ¶ 5. The Specification additionally teaches that extraction of such electrons generally requires that the electrodes have a work function that is sufficiently low to collect the electrons from the LUMO energy level of the photoelectric active material. Id. The application at issue describes a process for producing a low work function electrode where “[a]n ethoxylated polyethyleneimine (PEIE) layer is spray coated over the electrode layer.” Id. ¶ 8. In the alternative, an “optional metal oxide nanoparticle layer may be deposited over the electrode layer and the PEIE layer spray coated over the metal oxide nanoparticle layer.” Id. Appeal 2019-004682 Application 15/152,936 3 Claim 1 is illustrative of the subject matter on appeal and is reproduced below with certain limitations bolded for emphasis: A process for producing a photovoltaic system comprising: depositing a first electrode layer over a substrate; spray coating a metal oxide nanoparticle layer over the first electrode layer; spray coating an ethoxylated polyethyleneimine (PEIE) layer over the metal oxide nanoparticle layer; depositing a bulk heterojunction active layer over the PEIE layer; and depositing a second electrode layer over the bulk heterojunction active layer. Appeal Br. 26 (Claims App.) (reformatted for clarity) (emphasis added). REFERENCES The Examiner relies upon the following prior art: Name Reference Date Mano US 4,229,838 Oct. 28, 1980 Wakata US 2002/0064633 A1 May 30, 2002 Hasegawa US 2003/0108751 Al June 12, 2003 Brabec US 2007/0181179 Al Aug. 9, 2007 Jen US 2009/0188558 A1 July 30, 2009 Taillemite US 2013/0283794 A1 Oct. 31, 2013 Li-Min Chen et al., Multi-Source/Component Spray Coating for Polymer Solar Cells, ACSNANO Vol. 4, No. 8, 4744–4752 (2010). Yinhua Zhou et al., A Universal Method to Produce Low-Work Function Electrodes for Organic Electronics, Science Vol. 336, 327–332 (2012). Jae Won Shim et al., Studies of the optimization of recombination layers for inverted tandem polymer solar cells, Solar Energy Materials & Solar Cells 107, 51–55 (2012). Appeal 2019-004682 Application 15/152,936 4 REJECTIONS The Examiner maintains the following rejections: 1. Claims 1, 3, 7, 12, 14, 21, and 22 are rejected under 35 U.S.C. § 103 as being unpatentable over Shim in view of Chen and Jen. Final Action dated Sept. 25, 2018 (“Final Act.”) 3–4. 2. Claims 4, 5, 15, and 16 are rejected under 35 U.S.C. § 103 as being unpatentable over Shim in view of Chen, Jen, and Taillemite. Id. at 4. 3. Claims 6, 8, 17, and 19 are rejected under 35 U.S.C. § 103 as being unpatentable over Shim in view of Chen, Jen, and Zhou. Id. at 4–5. 4. Claims 9 and 18 are rejected under 35 U.S.C. § 103 as being unpatentable over Shim in view of Chen, Jen, Zhou, and Hasegawa. Id. at 5. 5. Claim 10 is rejected under 35 U.S.C. § 103 as being unpatentable over Shim in view of Chen, Jen, Zhou, and Brabec. Id. at 5–6. 6. Claims 11 and 20 are rejected under 35 U.S.C. § 103 as being unpatentable over Shim in view of Chen, Jen, Zhou, Wakata, and Mano. Id. at 6. DISCUSSION Rejection 1. The Examiner rejects claims 1, 3, 7, 12, 14, 21 and 22 as obvious over Shim in view of Chen and further in view of Jen. Id. at 3–4. In support of the rejection, the Examiner finds that Shim teaches forming a solar cell by depositing an indium-tin oxide (ITO) electrode on a glass substrate, coating a polyethyleneimine ethoxylated (PEIE) layer directly Appeal 2019-004682 Application 15/152,936 5 over the ITO electrode, depositing a bulk heterojunction layer over the PEIE layer, and depositing a silver electrode over the bulk heterojunction. Id. at 3. The Examiner finds that Shim fails to teach 1) that the PEIE layer is applied by spray coating and 2) that a metal oxide nanoparticle layer is applied to the first electrode. Id. at 3–4. The Examiner finds that Chen teaches a method of forming a polymer solar cell and explains that the layers of the cell can be applied via spray coating. Id. at 3. The Examiner determines that one of ordinary skill in the art would have had reason to use the spray coating of Chen to deposit the PEIE layer of Shim “in order to have applied a large-area uniform film with the predictable expectation of success.” Id. at 3–4. The Examiner further finds that Jen teaches a process of making a solar cell that “includes depositing a layer of zinc oxide nanoparticles onto the first electrode in order to improve the work function of the electrode.” Id. at 4. The Examiner determines that one of ordinary skill in the art would have had reason to use a layer of zinc oxide nanoparticles on the first electrode of Shim in order to have improved the work function of the electrode. Id. Appellant alleges error on several bases. We first address Appellant’s arguments regarding the Examiner’s prima facie case and next consider its arguments regarding criticality. Spray Coating Appellant argues that the references do not teach to spray coat an ethoxylated PEIE layer over a metal oxide nanoparticle layer. Appeal Br. 9– 13. The Specification provides the following definitions of “spray coating” and “spin coating”: Appeal 2019-004682 Application 15/152,936 6 Spray coating – “a coating process comprising atomizing or aerosolizing a liquid coating composition in a compressed gas stream functioning as a carrier medium that propels the coating composition, targeting the carrier gas comprising the coating composition into contact with a substrate, and depositing the coating composition from the carrier gas stream onto the substrate forming a coating layer.” Spin coating – “a batch process requiring the use of specialized equipment that spins the deposition substrate to spread the coating material by centrifugal force.” Spec. ¶¶ 26–27. Appellant points out that Shim teaches to apply the PEIE layer by spin coating rather than spray coating. Appeal Br. 9; Shim 52 (“A 10 nm-thick PEIE layer was spin casted onto the substrates in air.”). Appellant further points out that Jen does not teach a PEIE layer. Appeal Br. 9. Appellant asserts that, although Chen teaches spray coating of certain polymer coatings, it does not “teach or suggest a PEIE layer, let alone that PEIE can be spray coated.” Id. at 10. Chen teaches, in part, as follows: Spin-coating is the dominant fabrication method in polymer solar cell research; however, it is neither high throughput nor scalable. To realize these requirements, a myriad of deposition methods such as inkjet printing, screen printing, doctor blading, and spray coating have all been adopted to pursue success in large area coating. Amongst them, spray coating is capable of delivering large-area, uniform large polymer thin films through a relatively simple process, offering ample processing possibilities of engineering the film structure. In this method, the film evolution is a reconstitution process whereby solution particles are atomized and driven by a carrier gas onto the substrate; therefore, the droplets and resulting domain sizes can be finely tuned via controlled atomization. Films with a broad range of Appeal 2019-004682 Application 15/152,936 7 concentration and composition can be delivered via the spray coating method, thus allowing for the straightforward processing of polymers with poor solubility, as well as organic and inorganic materials with varying degrees of solubility/dispersity in the liquid phase. This opens up a whole new category of applications in materials chemistry. Chen 4744. Appellant quotes brief portions of Chen regarding film drying time and dissolution of the film underlayer without clear explanation as to such teaching’s applicability to spray coating of PEIE. Appeal Br. 10, 16. Appellant additionally argues that spin casting and spray coating are non-interchangeable processes. Id. at 10. In support, Appellant asserts that “spin casting is limited to very flat surfaces and cannot coat a rough surface effectively” while spray casting can coat a rough surface. Id. Appellant cites the Specification’s teaching that “multi-layer spray coating process avoids the functional surface area constraints imposed by other deposition techniques, such as spin [casting], for example, and may be used to produce large-area organic photovoltaic systems with relatively high through-put.” Id. at 10–11 (Spec. ¶ 22). This is not persuasive of nonobviousness. The foregoing distinctions merely point out the known advantages of spray coating. These factors tend to weigh in favor of one of ordinary skill in the art having reason to employ spray coating. Appellant further submits evidence that “the formulation of the PEIE layer as disclosed in Shim could not be spray coated by the process of Chen and achieve repeatable and sufficient adhesion to the underlayer.” Id. at 11 (citing the Declaration of Giorgio Cardone (hereinafter “Cardone Declaration”)). This is not persuasive. The Examiner finds that “it is well understood in the art that any solution, having its viscosity properly adjusted, is suitable for spraying.” Examiner’s Answer dated March 19, 2019 Appeal 2019-004682 Application 15/152,936 8 (“Answer”) 4. The Examiner further finds that it is known to make appropriate adjustments. As the Examiner explains in the Answer, [t]he [E]xaminer is not suggesting that the spin coating step of Shim be simply replaced with spraying and nothing else must change. A person of ordinary skill in the art, looking at Chen, would have understood that spray coating involves additional considerations to provide satisfactory results and would have included these additional considerations in any process modified to use spray coating. Answer 4. Further, as the Examiner observes, “the declaration does not provide any evidence concerning PEIE.” Id. at 5. Accordingly, Appellant’s argument that “formulations for PEIE used for spin casting may not be able to be spray coated” is not persuasive. PEIE Layer over the Metal Oxide Layer Appellant argues that the cited references do not teach to apply a PEIE layer over a metal oxide nanoparticle layer. Appeal Br. 13–14. The Examiner finds that Shim teaches to apply a PEIE layer to an electrode layer. Final Act. 3. The Examiner further finds that Jen teaches to deposit a layer of zinc oxide nanoparticles onto the first electrode layer to improve the work function of the electrode. Id. at 4. The Examiner concludes that one of ordinary skill in the art would have had reason “to have deposited a layer of zinc oxide nanoparticles on the first electrode of Shin before depositing the PEIE layer (i.e. and therefore depositing the PEIE layer directly onto the nanoparticle layer) in order to have improved the work function of the electrode.” Id. Appellant argues that the Examiner’s conclusion is “unsupported and conclusory.” Appeal Br. 13. Appellant contends that the references Appeal 2019-004682 Application 15/152,936 9 “applied separately or in combination do not teach or suggest how (e.g., which order) to apply both a PEIE layer and a metal oxide nanoparticle layer.” Id. at 14. Appellant further directs us to Jen’s teaching that the metal oxide nanoparticle layer can be intermediate the electron-conducting electrode and the monolayer or intermediate the photovoltaic layer and the monolayer. Id. (citing Jen ¶ 46). In view of such teachings, Appellant contends that “the record is devoid of any teaching or suggestion of the order in which a PEIE layer and a metal oxide nanoparticle layer would be applied.” Id. This is not persuasive. Jen teaches an embodiment where a thin layer of ZnO nanoparticles are spin-coated onto the electrode. Jen ¶ 129. The Examiner may rely on such teaching. See Merck & Co., Inc. v. Biocraft Labs., Inc., 874 F.2d 804, 807 (Fed. Cir. 1989) (“[A]ll disclosures of the prior art, including unpreferred embodiments, must be considered.”). In the Answer, the Examiner concludes that “Jen explains that forming the zinc oxide nanoparticle layer onto the first electrode improves the work function of the electrode and it would have been obvious . . . to have incorporated this featured into Shim in order to have improved the work function of the electrode.” Answer 6. Appellant has not shown error in such reasoning. Reasonable Expectation of Success Appellant further argues that the Examiner has not adequately shown that the results of the proposed combination would have been predictable. Appeal Br. 15–18. Appellant contends that the Examiner has not adequately addressed differences in the drying time of a PEIE layer that is spin cast as opposed to spray coated and the resulting differences in work function of the electrode. Id. at 16. Appellant further contends that Chen (which the Appeal 2019-004682 Application 15/152,936 10 Examiner relies on to teach spray coating) does not teach the spray coating of a PEIE layer. Id. at 17. In the Answer, the Examiner reasons that “one of ordinary skill in the art would have understood the results [of the combination] to be predictable because one of ordinary skill in the art would have understood the variables involved.” Answer 8. The Examiner further determines that “Chen teaches that the polymer layers in a solar cell (such as Shim’s PEIE) can be spray coated instead of spin casted. Thus, the intended purpose of forming a functional solar cell would have worked in this combination.” Id. Appellant has not shown error in the Examiner’s reasoning. As our reviewing court has explained, “[o]bviousness does not require absolute predictability of success. . . . For obviousness under § 103, all that is required is a reasonable expectation of success.” In re Kubin, 561 F.3d 1351, 1360 (Fed. Cir. 2009). Here, the Examiner has put forward a reasoned basis as to why a person of ordinary skill in the art would have been motivated to use a spray coating method and to apply a metal oxide layer to an electrode. Appellant directs us to certain differences between the processes, such as drying time, but does not show error in the Examiner’s finding that, in view of Chen’s teachings regarding the general applicability of spray coating and Jen’s teaching regarding application of a zinc oxide to an electrode, one of skill in the art would have determined that such combination had at least a reasonable expectation of success. In view of the foregoing, we determine that Appellant has not shown error in the Examiner’s prima facie case of obviousness of claims 1, 3, 7, 12, 14, 21, and 22 (subject to Rejection 1). Appeal 2019-004682 Application 15/152,936 11 Unexpected Benefits Appellant additionally argues that the claimed method yields unexpected benefits. Appeal Br. 11–12 (regarding claims 1 and 12), 14 (regarding claims 1 and 12), 19 (regarding claims 21 and 22), and 20–21 (regarding claims 3 and 14). Appellant argues that the inventors discovered “several unexpected alterations in the application of PEIE that could positively affect uniform surface coverage and electrical efficiency of the photovoltaic system utilizing spray coating.” Id. at 11. Appellant argues that the addition of a zinc oxide nanoparticle layer between the electrode and the PEIE layer improved the charge transport of the photovoltaic system. Id. In support of these assertions, Appellant refers to the Cardone Declaration. The Cardone Declaration includes the following statements: “[I]t was surprisingly found that . . . . the addition of a zinc oxide nanoparticle layer between the electrode prior and the PEIE or bulk heterojunction active layer resulted in more uniform surface coverage by the PEIE and bulk heterojunction active layer and improved the charge transport of the photovoltaic system.” Cardone Declaration ¶ 9. “It was surprisingly found that the zinc oxide nanoparticle layer improved the surface coverage of the PEIE layer and bulk heterojunction layer on the electrode layer.” Id. “[I]t it was surprisingly found that a spray coated zinc oxide nanoparticle layer had improved electrical efficiency and a spin coated zinc oxide nanoparticle layer negatively affected the electrical efficiency of the photovoltaic system.” Id. ¶ 11. Appeal 2019-004682 Application 15/152,936 12 The Examiner finds this showing not to be commensurate with the scope of claim 1 as “claim 1 is more broadly directed to metal oxides, not the limited species of zinc oxides.” Final Act. 2. The Examiner further determines that “the only statements in the declaration directed to the surprising results associated with the metal oxide layer (§ 9, 10, and 11 of the declaration) are merely conclusory statements which provide no evidence to support them.” Answer 9. The Examiner makes a similar determination regarding statements in the declaration regarding claims 3 and 14. Id. In general, an applicant may overcome a prima facie case of obviousness by establishing that a claimed feature “is critical, generally by showing that the claimed range achieves unexpected results relative to the prior art.” In re Geisler, 116 F.3d 1465, 1469–70 (Fed. Cir. 1997) (citation omitted). “Although it is well settled that comparative test data showing an unexpected result will rebut a prima facie case of obviousness, the comparative testing must be between the claimed invention and the closest prior art.” In re Fenn, 639 F.2d 762, 765 (CCPA 1981). Moreover, “[i]t is well settled that unexpected results must be established by factual evidence. Mere argument or conclusory statements in the specification does not suffice.” In re De Blauwe, 736 F.2d 699, 705 (Fed. Cir. 1984), quoted with approval in In re Soni, 54 F.3d 746, 750 (Fed. Cir. 1995). We agree with the Examiner that the scope of the Declaration is not commensurate with the claims (other than claims 3 and 14) because the Declaration is limited to a zinc oxide nanoparticle layer while most of the claims require only a metal oxide nanoparticle layer. Further, Appellant fails to supply comparative test data. Appellant does not supply data for the inventive process (nor for a product made by such process) nor for the Appeal 2019-004682 Application 15/152,936 13 closest prior art. Accordingly, Appellant has not shown adequate evidence of unexpected results sufficient to establish the criticality of the claimed process. In view of all of the foregoing, Appellant has not shown error with regard to the rejection of claims 1, 3, 7, 12, 14, 21, and 22. Rejections 2 and 3. The Examiner rejects claims 4, 5, 15, and 16 as obvious over Shim in view of Chen, Jen, and Taillemite. Final Act. 4 (Rejection 2). The Examiner additionally rejects claims 6, 8, 17, and 19 as obvious over Shim in view of Chen, Jen, and Zhou. Id. at 4–5 (Rejection 3). Appellant alleges error in these rejections on the same basis as with regard to Rejection 1. Appeal Br. 6. As we have not found such arguments to be persuasive, we determine that Appellant has not shown error with regard to claims 4, 5, 6, 8, 15–17, and 19. Rejection 4. The Examiner rejects claims 9 and 18 as obvious over Shim in view of Chen, Jen, Zhou, and Hasegawa. Final Act. 5. Claim 9 depends from claim 8 and further requires that “the spray coated silver layers are formed from the reaction products of a Tollens’ reaction.” Appeal Br. 27 (Claims App.). Claim 18 is similar. Id. at 28. The Examiner finds that Zhou teaches that silver is a suitable material for an electrode and Hasegawa teaches a method of forming a silver layer wherein the silver is formed from a Tollens’ reaction. Final Act. 5. Appellant argues that “it was surprisingly discovered that the reactants for the Tollens’ reaction could be spray coated and would begin to react as the formulation was being sprayed onto a surface to form the silver layer.” Appeal Br. 21. As a consequence, “the silver layer could be dried at room Appeal 2019-004682 Application 15/152,936 14 temperature without baking the electrode in an oven which can be advantageous for large format electrodes.” Id. at 21–22. In support of this argument, Appellant relies on the Cardone Declaration. The Cardone Declaration states that commercially available silver pastes are not suitable for spray coating due to their viscosity. Cardone Declaration ¶ 12. The Declaration further states as follows: It was surprisingly discovered that the reactants for the Tollens’ reaction could be spray coated and would begin to react as the formulation was being sprayed onto a surface to form the silver layer. Thereafter, the silver layer could be dried at room temperature without baking the electrode in an oven which can be advantageous for large format electrodes. Id. The Specification teaches “a Tollens’ reaction in which silver nitrate in an aqueous ammonia solution is reduced to silver metal during the spraying by reaction with an aldehyde-containing compound.” Spec. ¶ 32. The Specification further teaches that “[t]he spray coating of metallic silver layers is generally described, for example, in European Patent Publication Nos. 0 346 954 A2 and 1 469 099 A1, which are both incorporated by reference into this specification.” Id. In addition, Hasegawa, relied on by the Examiner, teaches formation of a silver plate layer. Hasegawa ¶ 79. Specifically, Hasegawa teaches “an ammoniac silver nitrate (Ag(NH3)2+OH-) solution (Tollens’ reagent) and a reducing agent solution are applied onto the surface of the basecoat layer 13 while they are mixed thereon to induce redox reaction to thereby deposit the metal silver (Ag) to form the metal plate layer.” Id. As above, an unexpected result must be shown by comparative testing between the claimed invention and the closest prior art. Further, conclusory Appeal 2019-004682 Application 15/152,936 15 statements are insufficient. The Specification indicates that the spray coating of metallic silver layers is known in the art. This is consistent with the cited prior art. Neither Appellant’s brief nor the Declaration presents comparative data (or substantive discussion) regarding prior art spray coating of metallic silver layers (or relevant drying characteristics) and that of the claims. Accordingly, Appellant has not shown that a process for the formation of a spray coated silver layer from the reaction products of a Tollens’ reaction yields an unexpected benefit commensurate with the claims. Rejection 5. The Examiner rejects claim 10 as obvious over Shim, Chen, Jen, and Zhou in light of Brabec. Final Act. 5–6. Appellant alleges error on the same basis as with regard to Rejection 1. Appeal Br. 6. As we have not found such arguments to be persuasive, we determine that Appellant has not shown error with regard to claim 10. Rejection 6. The Examiner rejects claims 11 and 20 as obvious over Shim, Chen, Jen and Zhou in light of Wakata and Mano. Final Act. 6. Claim 11 depends from claim 1 and further requires that the PEIE formulation “is spray coated using a formulation consisting of PEIE, water, and optionally ethanol, 2-propanol, or isopropanol, or any combination of ethanol, 2-propanol, or isopropanol wherein the formulation is substantially free of methoxyethanol.” Appeal Br. 27 (Claims App.). Claim 20 depends from claim 12 and is similar in scope. Id. at 28. The Examiner finds that Chen teaches that “spraying polymers is done from a dispersion.” Final Act. 6. The Examiner further finds that Wakata teaches that water is a suitable dispersing agent for spraying polymers to Appeal 2019-004682 Application 15/152,936 16 form a layer. Id. (citing Wakata ¶ 139). The Examiner additionally finds that Mano teaches that suitable solvents for PEIE include water combined with methanol or ethanol. Id. (citing Mano, col. 4:64–5:12). In view of the foregoing, the Examiner determines that it would have been obvious to employ a formulation of methanol or ethanol in combination with aqueous PEIE. Id. Appellant argues that one of ordinary skill in the art would not have had reason to combine the teachings of Mano with those of Shim and Chen. Appeal Br. 23. Appellant argues that Mano is directed to “an antithrombic vascular prosthesis” and does not teach or suggest spray coating. Id. Appellant further asserts that “[t]here is no[] teaching or suggestion in the prior art of record that methoxyethanol could be removed from Shim’s PEIE layer and achieve the desired work function or that one of ordinary skill in the art would [remove] methoxyethanol from Shim’s PEIE layer.” Id. The Examiner determines that the use of methanol or ethanol (as taught by Mano) as a solvent for PEIE is the mere “simple substitution of one known element for another to obtain predictable results.” Final Act. 6. Appellant does not show error in, or even squarely address, this determination. Appellant additionally argues that Wakata is not analogous art. Appeal Br. 23–24. Appellant argues that Wakata is from a different field of endeavor and, additionally, is not reasonably pertinent to the problem at issue. Id. Appellant similarly argues that Mano is neither from the same field of endeavor as Appellant’s claims nor pertinent to the problem faced by the Appellant. Id. References qualify as prior art for an obviousness determination only when analogous to the claimed invention. In re Clay, 966 F.2d 656, 658 Appeal 2019-004682 Application 15/152,936 17 (Fed. Cir. 1992). Two separate tests define the scope of analogous prior art: (1) whether the art is from the same field of endeavor, regardless of the problem addressed and, (2) if the reference is not within the field of the inventor’s endeavor, whether the reference still is reasonably pertinent to the particular problem with which the inventor is involved. In re Deminski, 796 F.2d 436, 442 (Fed. Cir.1986); see also In re Wood, 599 F.2d 1032, 1036 (CCPA 1979). Here, the inventors indicate that “[t]he thickness and density of a spray coated PEIE layer may be controlled by setting the spray coating process parameters, including . . . the composition of the PEIE coating solution (e.g., solvent composition, PEIE concentration, and the like).” Spec. ¶ 28. The Specification further teaches that “[t]he aqueous formulation used for spray coating a PEIE layer according to the present invention may include a non-toxic alcohol co-solvent or additive such as, for example, ethanol or isopropanol.” Id. ¶ 29 (emphasis added). Similarly, the Specification teaches that [a]n aqueous formulation for spray coating a PEIE layer used in accordance with the present invention may consist of PEIE and water. Alternatively, an aqueous and/or alcohol-based formulation for spray coating a PEIE layer may consist of PEIE, water, and isopropanol, for example, or may consist of PEIE, water, and ethanol, for example. Id. Thus, the Specification addresses spray coating process parameters. The Examiner finds that Wakata teaches that water is a suitable dispersing agent for spraying polymers used to form a layer. Final Act. 6 (citing Wakata ¶ 139). Wakata teaches that a method of applying the coating solution (second coating solution) containing the polymer according to the present invention which is prepared in the form of a water dispersion . . Appeal 2019-004682 Application 15/152,936 18 . include . . . a method of atomizing the second coating solution by a spraying method or the like. Wakata ¶ 139. Wakata’s teaching regarding use of water as a dispersing agent for spraying polymers to form a layer is reasonably pertinent to the inventors’ stated problem of controlling the spray coating process parameters. The Examiner additionally finds that Mano is analogous art because it is reasonably pertinent to the particular problem with which the inventor is involved. Answer 9. More specifically, the Examiner finds that Mano concerns forming a PEIE solution. Id. We look to the cited portion of Mano to determine if it is reasonably pertinent. Mano teaches that “[w]ater is suitable as a solvent for the polyethyleneimine” (Mano, col. 4:64–65) and “[s]ince polyethyleneimine is also soluble in a lower alcohol such as methanol, ethanol or ethylene glycol, the polyethyleneimine may be dissolved in such a solvent and the porous tubing can be impregnated directly with such a solution” (id. at col. 5:8–12). Thus, while Mano and the present application may be from different fields of endeavor, both address PEIE solutions. Accordingly, the Examiner’s determination that Mano is reasonably pertinent to the problem faced by the inventors, and therefore analogous art, is consistent with record evidence. Appeal 2019-004682 Application 15/152,936 19 CONCLUSION For the reasons set forth in the Final Action, the Examiner’s Answer, and above, the Examiner’s rejections are affirmed. In summary: Claims Rejected 35 U.S.C. § Reference(s)/Basis Affirmed Reversed 1, 3, 7, 12, 14, 21, 22 103 Shim, Chen, Jen 1, 3, 7, 12, 14, 21, 22 4, 5, 15, 16 103 Shim, Chen, Jen, Taillemite 4, 5, 15, 16 6, 8, 17, 19 103 Shim, Chen, Jen, Zhou 6, 8, 17, 19 9, 18 103 Shim, Chen, Jen, Zhou, Hasegawa 9, 18 10 103 Shim, Chen, Jen, Zhou, Brabec 10 11, 20 103 Shim, Chen, Jen, Zhou, Wakata, Mano 11, 20 Overall Outcome 1, 3–12, 14–22 No time period for taking any subsequent action in connection with this appeal may be extended under 37 C.F.R. § 1.136(a). AFFIRMED Copy with citationCopy as parenthetical citation