DETAILED ACTION
This is the fourth Office Action regarding application number 17/962,101, filed on 10/07/2022, which claims priority to provisional application number 63/253,936, filed on 10/08/2021.
This action is in response to the Applicant’s Response received 12/24/2025.
Status of Claims
Claims 1, 2, 4, 9-21, 23-25, 32, and 33 are currently pending.
Claims 3, 5, 8, 22, and 26-31 are canceled.
Claims 1, 2, 9, 13, and 18-20 are amended.
Claims 12 and 19 are withdrawn.
Claims 1, 2, 4, 9-11, 13-18, 20, 21, 23-25, 32, and 33 are examined below.
The rejection of claim 5 under 35 U.S.C. § 103 has been withdrawn in light of the Applicant’s amendments.
Upon further examination, the Office has set forth a new ground of rejection.
No claim is allowed.
Response to Arguments
The Applicant’s arguments received 12/24/2025 have been carefully considered but they are moot in light of the Office’s new ground of rejection.
The applicant first argues that “thermal formed” recitation is not taught by prior art and 103 rejections should be withdrawn. Please see examiner’s findings below that this is only a recitation of a product-by-process, and does not overcome the obviousness conclusion.
The applicant next argues that the prismatic structure height is not taught by the prior art. The narrower range necessitated a new ground of rejection and is moot.
The applicant finally argues that the combination of prior art references does not teach the recited limitation of “light collection efficiency greater than 90% for light at a zenith angle of 75 degrees”. The examiner does not at this time find the applicant’s response compelling. The examiner previously wrote a comprehensive explanation describing exactly why skilled artisans would find it obvious to produce a solar sheet to have the recited collection efficiency. The examiner does not understand any of the applicant’s remarks to in any way address or respond to these findings of fact and conclusions. The applicant speculates that SAMUELS does not disclose comparable efficiency, but this is not responsive to the ground of rejection, and is considered only to be attorney argument. The examiner concludes that the prior art references teach the prismatic structures having the same dimensions and materials as the applicant’s, and requests technical and experimental documentation from the applicant/inventor establishing that the claimed prismatic structures perform differently.
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 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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1, 2, 4, 9, 11, 13-18, 20, 23-25, 32, and 33 are rejected under 35 U.S.C. 103 as being unpatentable over PAN (US 2017/0015430 A1) in view of SAMUELS (US 2015/0285959 A1) and YANAGAWA (KR 20130091517 A).
Regarding claim 1, PAN teaches a solar sheet, comprising:
a plurality of thin film solar cells (Fig. 3). PAN’s Figure 3 illustrates that the solar sheet should be flexible.
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PAN also discloses a polymer sheet (98) overlaying a light receiving surface of the plurality of thin film solar cells, a bottom surface of the flexible polymer sheet faces the plurality of thin film solar cells and a top surface of the flexible polymer sheet forms an air-material interface of the solar sheet (Figs. 17A and 17B). PAN further suggests that the top-most transparent layer (98) of the solar sheet should be Teflon, a material known to have light transmissivity greater than 85% for at least one wavelength between 400-1500nm. PAN’s solar cells may also include InGaP/GaAs/InGaAs (para. 83; same triple junction solar cell as applicant’s disclosed at Figure 5).
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PAN does not disclose expressly that the polymer sheet has a plurality of prismatic structures.
SAMUELS teaches a polymer sheet overlaying a light receiving surface of the plurality of thin film solar cells, a bottom surface of the flexible polymer sheet faces the plurality of thin film solar cells and a top surface of the flexible polymer sheet forms an air-material interface of the solar sheet, the top surface having a plurality of prismatic structures operative to refract light towards the plurality of solar cells (Fig. 16 illustrates a polymer sheet on solar cells with top surface prismatic structures refracting light down to the cells).
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Skilled artisans would have found it obvious to modify PAN and design the top surface of its polymer sheet to instead have a plurality of prismatic structure to refract light down towards the solar cells are taught by SAMUELS in order to capture light directed at incident angles (SAMUELS, para. 81), among other advantageous reasons of capturing as much light as possible and prevent waste of incident sunlight.
Although SAMUELS suggests that its prismatic sheet uses a hardened material, the examiner finds that it would have been obvious to employ a flexible material for this sheet as well because PAN teaches that the sheets should “be flexible to conform to an underlying rounded surface, e.g., the surface of a wing or the surface of a fuselage of a UAV)” (para. 63). The examiner also emphasizes that the PTFE/Teflon material of PAN’s top sheet is not substituted, only re-shaped to have a different surface configuration.
YANAGAWA teaches prismatic structure with height of 30-60 micrometers to maximize light concentration efficiency (Fig. 5, para. 74).
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Skilled artisans would have found it obvious to modify PAN and make the height of each prismatic structure between 10-30 micrometers to maximize light concentration efficiency as taught by YANAGAWA. The examiner asserts that the height range taught by YANAGAWA overlaps and is close enough to render the entire claimed range prima facie obvious.
PAN and SAMUELS do not disclose explicitly that (1) the flexible polymer sheet has a transmissivity greater than 85% for each light wavelength between 400 nm and 1500 nm, or (2) the solar sheet has a light collection efficiency of the solar sheet for light at a zenith angle of 75° is greater than 90%.
SAMUELS, however, explains that the prism angle may be from about 5-85 degrees, but typically are selected be closer to about 45 degrees (para. 69). SAMUELS also explains that the size of the prism lens may vary broadly depending upon the nature of the application (para. 67). SAMUELS continues explaining that skilled artisans would find it preferable that the material of the prism lens “may be substantially completely transparent to the radiation being handled” (para. 70). SAMUELS also shows that light is collected even when it impinges the prisms at angles horizontal to its planar surface (i.e., 90 degrees) (Fig. 16 and paras. 82-83). If the prism layer is oriented perfectly horizontal to the Earth’s surface, then this 90 degree angle also would represent the sun’s zenith angle. SAMUEL’s various figures illustrate angles between negative 90 to positive 90 degrees, and that this light is preferably redirected using the prisms toward an intended target such as a solar cell for conversion into useful electrical power.
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The examiner finds that the sheet of the prior art is substantially identical to the sheet recited, and that skilled artisans would expect and desire the light collection efficiency of the sheet to exceed 90% because this would improve overall device performance. There are few other motivators more powerful that a desire to improve light collection efficiency, and skilled artisans would very much want to make the necessarily improvements to increase this efficiency value. Further, the examiner finds that the sheet of the prior art is substantially identical to the sheet recited, and that skilled artisans would expect and desire the transmissivity of the sheet to exceed 85% across the claimed wavelengths because this would improve overall device performance (and because PAN remarks that the prism material may be substantially completely transparent to the radiation being handled). There are few other motivators more powerful that a desire to improve light collection efficiency via improvements in transmissivity of the front layer, and skilled artisans would very much want to make the necessarily improvements to increase this efficiency value. The examiner further asserts that the Teflon material disclosed by PAN, when it is modified according to SAMUEL’s teachings, is disclosed by the applicant to satisfy the claimed optical performance requirements.
Regarding product and apparatus claims, when the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent. It is well settled that where there is a reason to believe that a functional characteristic would be inherent in the prior art, the burden of proof then shifts to the applicant to provide objective evidence to the contrary. In re Schreiber, 128 F.3d at 1478, 44 USPQ2d at 1478, 44 USPQ2d at 1432 (Fed. Cir. 1997) (see MPEP 2112.01).
Since the examiner does not have proper means to conduct experiments, the burden of proof is now shifted to applicants to show otherwise. In re Best, 562 F.2d 1252, 195 USPQ 430 (CCPA 1977); In re Fitzgerald, 205 USPQ 594 (CCPA 1980).
"[E]ven though product-by-process claims are limited by and defined by the process, determination of patentability is based on the product itself. The patentability of a product does not depend on its method of production. If the product in the product-by-process claim is the same as or obvious from a product of the prior art, the claim is unpatentable even though the prior product was made by a different process." MPEP 2113. The examiner asserts that the recitation “thermal formed” describes only the method of production and adds no other patentably distinctive feature or capability, and that the prisms of SAMUELS are physically identical and possess identical capability to prismatic structures that are “thermal formed”. There is no evidence of record or other information that suggests that the prisms of SAMUELS function any differently that the recited prismatic structures formed by a thermal-type process.
Regarding claim 2, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein the plurality of prismatic structures are configured to recapture light reflected from a surface of a thin film solar cell in the plurality of thin film solar cells (the angles of the prismatic surfaces would accomplish said function of reflecting back to the solar cell light that is reflected away from the surface of the solar cell).
Regarding claim 4, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein the flexible polymer sheet has a thickness in a range from 25 micrometers to 150 micrometers (heights of prisms can be 0.1 micrometer to 1mm, para. 67, and thickness of optional prism substrate 46 can be 0.1nm to 100mm, or 1-20 mm, para. 73 in SAMUELS; thus all overlapping with the claimed range).
Regarding claim 9, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein the plurality of prismatic structures includes inverted prism structures or prism structures that project outward from the top surface (SAMUELS illustrates both options).
Regarding claim 11, modified PAN teaches or would have suggested the solar sheet of claim 9, wherein each prism structure is a corner cube prism (SAMUELS, para. 38; para. 64 also suggests that prisms should have at least 3 or more sides, which would include a corner cube of 4 sides).
Regarding claim 13, modified PAN teaches or would have suggested the solar sheet of claim 1, but does not disclose explicitly that the plurality of prismatic structures is configured to increase a conversion efficiency of the plurality of solar cells for light at a zenith angle between 0° and 20°. However, the examiner finds that the sheet of the prior art is substantially identical to the sheet recited, and that skilled artisans would expect and desire the efficiency of the sheet to increase at various zenith angles because this would improve overall device performance. There are few other motivators more powerful that a desire to improve efficiency, and skilled artisans would very much want to make the necessarily improvements to increase this efficiency value.
Regarding product and apparatus claims, when the structure recited in the reference is substantially identical to that of the claims, claimed properties or functions are presumed to be inherent. It is well settled that where there is a reason to believe that a functional characteristic would be inherent in the prior art, the burden of proof then shifts to the applicant to provide objective evidence to the contrary. In re Schreiber, 128 F.3d at 1478, 44 USPQ2d at 1478, 44 USPQ2d at 1432 (Fed. Cir. 1997) (see MPEP 2112.01).
Since the examiner does not have proper means to conduct experiments, the burden of proof is now shifted to applicants to show otherwise. In re Best, 562 F.2d 1252, 195 USPQ 430 (CCPA 1977); In re Fitzgerald, 205 USPQ 594 (CCPA 1980).
Regarding claim 14, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein a sidewall angle of each prismatic structure is in a range from 15 to 75 degrees (SAMUELS, para. 69, overlapping range).
Regarding claim 15, modified PAN teaches or would have suggested the solar sheet of claim 14, wherein the sidewall angle is in a range from 45 degrees to 60 degrees (SAMUELS, para. 69, overlapping range).
Regarding claim 16, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein the flexible polymer sheet is configured to encapsulate the light receiving surface of the plurality of solar cells (PAN, Fig. 16, please see how the prismatic sheet directly contacts an upper surface of solar cells, such “encapsulating” the front light receiving surface).
Regarding claim 17, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein a specific power of the solar sheet is in a range from 1000 W/kg to 4500 W/kg (PAN, para. 13 demands that the solar system has a specific power range of 1500-4500 W/kg, overlapping with the claimed range).
Regarding claim 18, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein a characteristic dimension of each prismatic structure in the plurality of prismatic structures is greater than a wavelength of incident light (heights of prisms can be 0.1 micrometer to 1mm, SAMUELS, para. 67, overlaps with claimed range).
Regarding claim 20, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein a characteristic dimension of each prismatic structure in the plurality of prismatic structures is less than 500 micrometers (heights of prisms can be 0.1 micrometer to 1mm, SAMUELS, para. 67, overlaps with claimed range).
Regarding claim 23, modified PAN teaches or would have suggested the solar sheet of claim 1, further comprising an adhesive connecting the plurality of solar cells to the flexible polymer sheet (pressure sensitive adhesive, PAN, para. 109).
Regarding claim 24, modified PAN teaches or would have suggested the solar sheet of claim 23, wherein the adhesive is a pressure-sensitive adhesive layer (PAN, para. 109).
Regarding claim 25, modified PAN teaches or would have suggested the solar sheet of claim 1, wherein solar sheet is configured for installation on a surface of an unmanned aerial vehicle (UAV) or on a surface of a component of a UAV (see PAN, Fig. 1).
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Regarding claim 32, modified PAN teaches or would have suggested a method of improving flight time in an unmanned aerial vehicle (UAV), comprising:
providing a solar sheet according to claim 1 (see entire rejection of claim 1 above);
providing a power conditioning system configured to operate the solar sheet within a desired power range and configured to provide power in the form of a voltage compatible with an electrical system of the UAV;
installing the solar sheet to the UAV; and
connecting the power conditioning system with the electrical system of the UAV (PAN, para. 119 describes each of the steps).
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Regarding claim 33, modified PAN teaches or would have suggested an unmanned aerial vehicle (UAV), comprising:
a solar sheet according to claim 1 (see entire rejection of claim 1 above) installed on a surface of the UAV or on a surface of a component of the UAV; and
a power conditioning system configured to operate the solar sheet within a desired power range and configured to provide power in the form of a voltage compatible with an electrical system of the UAV (PAN, para. 119 describes a power conditioning circuit).
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Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over PAN (US 2017/0015430 A1) in view of SAMUELS (US 2015/0285959 A1) and YANAGAWA (KR 20130091517 A) as applied to claim 9 above, and further in view of CHUANG (US 2006/0256582 A1).
Regarding claim 10, modified PAN teaches or would have suggested the solar sheet of claim 9, but does not teach expressly that each prism structure is a linear or curvilinear prism.
CHUANG teaches a prism sheet with both pyramidal and linear prisms for a light guide plate of another optical device (Figs. 1 and 2). Linear prisms were known earlier than 2006, nearly 20 years ago. CHUANG makes it clear that the viewing angle is affected by the structure of the prisms (e.g., para. 9).
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Skilled artisans would have found it obvious to modify the prisms of PAN and change the shape and employ linear prisms as taught by CHAUNG in order to affect the desired angles that light is deflected through the prism sheet to the layers adjacent, depending on whether a designer wishes to have latitudinal and/or longitudinal convergence. The examiner also finds the modifications obvious because they simply are only a change in shape and there is no evidence of record in the applicant’s disclosure that any particular configuration is materially significant to the principle of operation or performance results. MPEP 2144.04(IV)(B).
Claim 21 is rejected under 35 U.S.C. 103 as being unpatentable over PAN (US 2017/0015430 A1) in view of SAMUELS (US 2015/0285959 A1) and YANAGAWA (KR 20130091517 A) as applied to claim 1 above, and further in view of ATWATER (US 2016/0056321 A1).
Regarding claim 21, modified PAN teaches or would have suggested the solar sheet of claim 1, but does not disclose expressly that the flexible polymer sheet can be flexed in two dimensions to a bend radius of 1 centimeter.
ATWATER teaches that flexible solar cells and modules effective for advanced aerospace applications, where a panel should have a minimum bend radius of 10 centimeters, and comments about the effect of layer dimensions in both an X and a Y axis (paras. 108 and 110). ATWATER recognizes the importance of flexibility and bending capability in aerospace applications, and further explains that the configuration and shape of elements should be arranged however is necessary to accomplish the design and application objectives (para. 109).
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Skilled artisans would have found it obvious to modify PAN and adjust the bend radius of the flexible polymer sheet to 1 cm because ATWATER teaches that the solar cell modules (and thus all of the comprising layers) must be selected in order to meet payload and space constraints generally (para. 102). Skilled artisans would clearly understand that a high degree of flexibility is extremely desirable for aerospace applications where space is limited and weight is a serious design and performance factor. Though ATWATER only describes an example of a 10 cm bend radius, skilled artisans would immediately realize the obviousness of selecting other bend radii as required to meet the minimum requirement for a particular aerospace application, and would find it obvious to adjust as necessary the bend radius requirement when needed, including to values of 1 cm. The examiner finds convincing evidence that ATWATER’s disclosure would enable skilled artisans to understand that smaller bend radii would be relatively easy to accomplish if desired because a relatively smaller bend radius such as 1cm requires a less demanding configuration and choice of materials. In general, greater bend radii require a greater consideration of design features so that the various components of the module do not fracture or become compromised.
Further, changing a bend radius from 10cm to 1cm is only an obvious change in size and dimension, and the modification would not cause any significant unexpected or surprising result in performance or operation. MPEP 2144.04(IV)(A).
Conclusion
No claim is allowed.
THIS ACTION IS MADE FINAL. 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 extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Contact Information
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANGELO TRIVISONNO whose telephone number is (571) 272-5201 or by email at <angelo.trivisonno@uspto.gov>. The examiner can normally be reached on MONDAY-FRIDAY, 9:00a-5:00pm EST. The examiner's supervisor, NIKI BAKHTIARI, can be reached at (571) 272-3433.
/ANGELO TRIVISONNO/
Primary Examiner
Prosecution Insights