Microstructure light-collecting film structure

Abstract

A microstructure optical film structure having a latitude position optimization function, used for a solar light-collecting module installed (operating) in a direction perpendicular (orthogonal) to sunlight or in a direction perpendicular (orthogonal) to ground, and a method for collecting sunlight or ambient light by the light-collecting film. The microstructure optical film module comprises a photovoltaic (PV) module, and the module is suitable for various inorganic / organic PV wafers / photoelectric sensors / modules thereof and comprises an optimized microstructure optical film layer which can receive light of various angles incident from different latitudes. On the basis of the orientation of the microstructure optical film, a microstructure profile defined within a specific latitude range is optimized to collect solar energy / ambient light in a direction perpendicular to sunlight or in a direction perpendicular to ground. The present invention directly overcomes the key issue in the solar industry of how to reduce the system cost while ensuring unit energy conversion efficiency.

Description

Microstructure light-collecting film structure Technical Field

[0001] The present invention relates to an optical film, particularly a microstructured light-collecting film structure having a latitude optimization function and suitable for installation / operation in a direction perpendicular to sunlight or perpendicular to the ground. Background Art

[0002] In the United States, California requires all new residential buildings to achieve net-zero emissions by 2020, and imposes the same requirement on commercial buildings by 2030 (CA Energy Efficiency Strategic Plan, California Public Utilities Commission, 2018. http: / / www.cpuc.ca.gov / General.aspx?id=4125). Therefore, due to these stringent energy policies and the abundant available surface area in the built environment, building-integrated photovoltaics (BIPV) have attracted people's attention. A recent study confirmed this idea, finding that 32% of the EU’s electricity needs could be met using BIPV alone (D. Mueller, Merck, H. Buerkstuemmer, R. Vignal, P. Mace, Technical Evaluation of BIPV power generation potential in EU-28. http: / / becquerelinstitute.org / wp-content / uploads / 2014 / 08 / 6DO-8-final-BIPV-Technical-Potential.pdf, 2016, 2518-2522), and as a result, research in this area is growing.

[0003] Proper installation and orientation of solar cells are fundamental to achieving optimal efficiency. Traditionally, solar panels are installed and oriented so that the panel surface is perpendicular (orthogonal) to the direction of incoming sunlight for the majority of the time. Essentially, the optimal orientation for a conventional solar panel is with its surface normal facing the sun. This orientation maximizes power generation efficiency because it maximizes the projected area of ​​the solar panel when viewed from the sun's direction. However, the sun moves across the sky throughout the day, reaching a different zenith (i.e., the height above the horizon at maximum noon) depending on the time of year. Ideally, conventional solar panels are installed in two main configurations. To maximize solar energy transmission efficiency, conventional solar panels are mounted on a system equipped with precision tracking modules. This system dynamically rotates the panels on two axes throughout the day (tracking the sun's azimuth and altitude), allowing them to track the sun. The tilt angle (the angle between the panel plane and the approximate plane of the Earth's surface at the panel's location) is also adjusted to compensate for the varying height of the sun above the horizon with sunrise, sunset, and seasonal variations. However, sun tracking systems rely on bulky mounting platforms, expensive and sensitive trackers, and are prone to failure and error (requiring a deviation of less than ±0.1°). Furthermore, many system installations are impractical in urban commercial areas. The second common approach is fixed installation. Traditionally, panels are mounted facing south (i.e., the ground projection of a surface perpendicular to the panel's active surface points south), with an inclination angle equal to the panel's latitude. The details above are based on the Northern Hemisphere; the Southern Hemisphere faces north instead.

[0004] Using conventional technology suitable for concentrating solar radiation or energy transferred via a medium onto a solar cell chip / element, the following concentrators have been disclosed, such as compound parabolic concentrator solar cells (CPCs); planar concentrators, such as holographic planar concentrator solar cells (HPCs), which include a flat highly transparent plate and a holographic recording optical element mounted on its surface or a hologram method for concentrating solar energy onto an adjacent photovoltaic chip; spectrum-splitting concentrator solar cells (SSCs), which include multiple single-junction photovoltaic cells, each of which is individually optimized to operate efficiently in its corresponding different spectral bands; and luminescent solar concentrators (LSCs), which are composed of a transparent plastic sheet containing absorbing and emitting materials with solar cells attached to the edge.

[0005] According to the literature, one of the technologies considered for BIPV is to incorporate luminescent solar concentrators (LSCs) into the building envelope. LSCs consist of transparent plastic sheets containing absorbing and emitting (fluorescent) materials, with solar cell wafers attached to the edges. LSCs have been shown to be able to effectively accept light at various incident angles without the need for a tracking system, an advantage often mentioned in many literatures but not yet widely explored in industrial applications. A wedge-shaped LSC (Performance of wedge-shaped luminescent solar concentrators employing phosphor films and annual energy estimation case studies, Renewable Energy 160 (2020) 513-525.) exhibited enhanced sunlight capture capabilities at incident angles of 20-40°. (MD Hughes, C. Maher, D.-A. Borca-Tasciuc, D. Polanco, D. Kaminski, Performance comparison of wedge-shaped and planar luminescent solar concentrators, Renew. Energy 52 (2013) 266e272, https: / / doi.org / 10.1016 / j.renene.2012.10.034.) Most LSC products use organic dyes, inorganic phosphors, or quantum dots as luminescent materials. These quantum dots and organic dyes are degraded by ultraviolet radiation, while inorganic phosphors cause significant scattering losses. (DKG de Boer, DJ Broer, MG Debije, W. Keur, A. Meijerink, CR Ronda, PPC Verbunt, Progress in phosphors and filters for luminescent solar concentrators, Optic Express 20 (2012) A395, https: / / doi.org / 10.1364 / oe.20.00a395.) For the above conventional technology, reference can be made to U.S. Patents US20130312811A1, US20150194555A1, and US20150107665A1.

[0006] A key issue currently facing the traditional solar industry is how to reduce system costs per unit of energy (kWh) converted. The mainstream technologies being explored to reduce the cost per kWh of solar energy have two main goals: first, improving the efficiency of solar cells, including those in solar modules, and second, transferring more solar radiation to solar cell wafers or components through a medium. Specifically, these technologies include the development of diffractive (grating / holographic) films, fluorescent polymers, and organic materials / dye-sensitized solar cells to replace expensive semiconductor-based solar cell wafers. Alternatively, they employ sun-tracking concentrating systems that utilize high-efficiency, small-area photovoltaic crystals (such as III-V compound semiconductors) and implement low-cost thermal collectors and solar cell concentrators. While these reductions in semiconductor-based solar cell wafers may offer significant potential, these traditional solar systems rely on extensive land use, even extending to reservoirs and ecological ponds. This irrational destruction of fertile farmland, pastures, and forests will ultimately be irreparable. Even more striking is the limited applicability of traditional solar modules and systems in urban residential areas, to the point of being practically useless. Globally, residential solar cell modules / systems (which can only be used in small, limited rooftop spaces) are typically manufactured using glass panels and aluminum frames made from traditional silicon solar cell wafers. Glass and silicon materials constitute the majority of the module's cost. Therefore, if a microstructured optical film with latitudinal optimization could be introduced within the framework of a standardized product module, it could be suitable for truly building-integrated solar modules / systems (BIPV / BIPVs) installed / operated perpendicular to sunlight or perpendicular to the ground, achieving efficient gain collection of sunlight or ambient light. This would significantly improve the system's power generation efficiency and reduce the levelized cost of electricity (LCOE).

[0007] Summary of the Invention

[0008] Based on the above reasons, one purpose of the present invention is to provide a microstructure light-collecting film structure. According to the facing directions of the different light-facing surfaces of the microstructure on the optical film, the microstructure profile defined within a specific latitude range is optimized to collect solar energy / ambient light in the direction perpendicular to the sunlight or perpendicular to the ground, so as to achieve a truly building-integrated solar module / system (BIPV / BIPVs) that efficiently collects sunlight or ambient light, thereby greatly improving the system's power generation efficiency and reducing the levelized cost of electricity (LCOE) per kilowatt-hour.

[0009] To achieve the above-mentioned purpose, the present invention provides a microstructure light-collecting film structure, comprising: a positive light-collecting optical film having a light-collecting surface; and a plurality of microstructures arranged in an array and disposed on the light-collecting surface of the positive light-collecting optical film, each of the microstructures comprising a bottom surface, a first light-facing surface, a second light-facing surface and a third light-facing surface, the first light-facing surface extending upward from one end of the bottom surface, and a first inner angle being formed between the first light-facing surface and the bottom surface, the second light-facing surface being connected to the first light-facing surface away from an end connected to the bottom surface and extending upward, and a second inner angle being formed between the second light-facing surface and the first light-facing surface, one end of the third light-facing surface being connected to the second light-facing surface away from an end connected to the first light-facing surface and extending downward, and the other end of the third light-facing surface being connected to the end of the bottom surface away from an end connected to the first light-facing surface and connected to various inorganic / organic photovoltaic chips / photoelectric sensors / and their modules.

[0010] In some embodiments, the third light-facing surface has an outward convex arc that is a free-curved surface.

[0011] In some embodiments, the microstructure light-concentrating film structure further includes an anti-reflection film coated on the microstructures, and the anti-reflection film has a first refractive index n1.

[0012] In some embodiments, each of the microstructures has a second refractive index n2, and the first refractive index n1 is smaller than the second refractive index n2.

[0013] In some embodiments, the forward light-collecting optical film has a third refractive index n3, and the second refractive index n2 is smaller than the third refractive index n3.

[0014] In some embodiments, the microstructure light-collecting film structure further includes an optical adhesive disposed below the forward light-collecting optical film. The optical adhesive has a fourth refractive index n4, and the third refractive index n3 is smaller than the fourth refractive index n4.

[0015] In some embodiments, the first interior angle is greater than or equal to 50° and less than or equal to 80°.

[0016] In some embodiments, the second interior angle is greater than or equal to 120° and less than or equal to 175°.

[0017] In some embodiments, the array arrangement is an array symmetrical arrangement, which at least includes a circular array symmetrical arrangement, a polygonal array symmetrical arrangement, and a single-axis array symmetrical arrangement.

[0018] In some embodiments, the array arrangement is a linear array arrangement, including at least a circular linear array arrangement, a polygonal linear array arrangement, and a single-axis linear array arrangement.

[0019] The above has generally summarized the technical features and advantages of the present disclosure so that the detailed description of the present disclosure below can be better understood. Other technical features and advantages that constitute the subject matter of the patent application of the present disclosure will be described below. Those with ordinary knowledge in the technical field to which the present disclosure belongs should understand that the concepts and specific embodiments disclosed below can be used to modify or design other structures or processes to achieve the same purpose as the present disclosure. Those with ordinary knowledge in the technical field to which the present disclosure belongs should also understand that such equivalent constructions cannot depart from the spirit and scope of the present disclosure as defined by the appended patent application. Description of the drawings

[0020] FIG1 is a top view schematically showing a first embodiment of a microstructure light-collecting film structure of the present invention, which is symmetrically arranged in a two-dimensional array for multi-dimensional light collection.

[0021] FIG. 2 a is a schematic cross-sectional view along the section line AA of FIG. 1 .

[0022] FIG. 2 b is a schematic cross-sectional view along the section line AA of FIG. 1 .

[0023] FIG3 is a top view of the first embodiment of the microstructure light-collecting film structure of the present invention, which is another symmetrical array arrangement for multi-dimensional light collection.

[0024] FIG. 4 a is a schematic cross-sectional view of the microstructured light-collecting film structure of the present invention applied to a solar module, taken along the section line BB of FIG. 3 .

[0025] FIG4 b is a cross-sectional view of the microstructured light-collecting film structure of the present invention applied to a solar module, taken along the section line BB of FIG3 .

[0026] FIG5 is a 3D top view of the microstructure light-collecting film structure of the present invention.

[0027] FIG6 a is a schematic cross-sectional view of the microstructure light-collecting film structure of the present invention installed perpendicularly (orthogonally) to the ground, along the section line CC of FIG5 .

[0028] FIG6 b is a schematic cross-sectional view of the microstructure light-collecting film structure of the present invention installed perpendicular (orthogonal) to the ground, along the section line CC of FIG5 .

[0029] FIG. 7 a is a top view schematically showing a multi-dimensional light-collecting structure of a second embodiment of the microstructure light-collecting film structure of the present invention arranged in a linear array.

[0030] FIG. 7 b is a top view schematically showing a multi-dimensional light-collecting structure of the second embodiment of the microstructure light-collecting film structure of the present invention arranged in another linear array.

[0031] FIG8 a is a schematic cross-sectional view of the microstructured light-collecting film structure of the present invention applied to a solar module, taken along the section line CC of FIG7 a .

[0032] FIG8 b is a schematic cross-sectional view of the microstructured light-collecting film structure of the present invention applied to a solar module, taken along the section line CC of FIG7 a .

[0033] FIG9 a shows an embodiment of the microstructure light-collecting film structure of the present invention installed (operating) in a direction perpendicular (orthogonal) to the ground.

[0034] FIG9 b shows an embodiment of the microstructure light-collecting film structure of the present invention installed (operating) in a direction perpendicular (orthogonal) to the ground.

[0035] FIG10 a shows an embodiment of the microstructured light-collecting film structure of the present invention being applied to a solar module for installation (operation) in a direction perpendicular (orthogonal) to the ground.

[0036] FIG10 b shows an embodiment of the microstructured light-collecting film structure of the present invention being applied to a solar module and installed (operated) in a direction perpendicular (orthogonal) to the ground.

[0037] FIG11 is a schematic diagram of a functional relationship curve between the photoelectric conversion efficiency of the microstructure light-collecting film structure of the present invention and the solar flux concentration.

[0038] In the picture:

[0039] 100: Microstructure light-collecting film structure

[0040] 200: Various inorganic / organic photovoltaic chips / photoelectric sensors / and their modules

[0041] 300: Microstructured solar energy module

[0042] 10: Positive light collecting optical film

[0043] 11: Finishing surface

[0044] 20: Microstructure

[0045] 21: First light-facing side

[0046] 22: Second light-facing side

[0047] 23: The third side facing the light

[0048] 24: Bottom

[0049] 30: Anti-reflective film

[0050] 40: Optical adhesive

[0051] A:First interior angle

[0052] a: curve

[0053] B:Second interior angle

[0054] b: curve

[0055] C:Third interior angle

[0056] c: curve

[0057] d: curve

[0058] F: convex arc

[0059] L1: Sunlight

[0060] L2: Sunlight

[0061] L3: Sunlight

[0062] n0: refractive index of air

[0063] n1: first refractive index

[0064] n2: second refractive index

[0065] n3: third refractive index

[0066] n4: fourth refractive index. DETAILED DESCRIPTION

[0067] The specific implementation of the present invention is described in detail below in conjunction with specific circumstances.

[0068] Figure 1 is a top view schematically illustrating a first embodiment of a microstructured light-collecting film structure of the present invention, arranged symmetrically in a two-dimensional array for multi-dimensional light collection. Figures 2a and 2b are schematic cross-sectional views taken along line AA of Figure 1. Figure 3 is a top view schematically illustrating a first embodiment of a microstructured light-collecting film structure of the present invention, arranged symmetrically in another array for multi-dimensional light collection. Figures 4a and 4b are schematic cross-sectional views of a microstructured light-collecting film structure of the present invention applied to a solar module, taken along line BB of Figure 3.

[0069] 1 and 2 a to 2 b , the microstructure light-collecting film structure 100 of the first embodiment of the present invention includes a forward light-collecting optical film 10 and a plurality of microstructures 20 .

[0070] The positive light-collecting optical film 10 may have a light-collecting surface 11. In some embodiments, the positive light-collecting optical film has a third refractive index n3.

[0071] Referring to Figures 1 and 3 , a plurality of microstructures 20 may be arranged in an array on the light-collecting surface 11 of the forward-light-collecting optical film 10 . The array arrangement may be a symmetrical array arrangement, including at least a circular array symmetrical arrangement, a polygonal array symmetrical arrangement, and a uniaxial array symmetrical arrangement. In Figure 1 , the array arrangement is a quadrilateral (offset) array symmetrical arrangement; in Figure 3 , the array arrangement is a quadrilateral (centered) array symmetrical arrangement.

[0072] Please refer to Figures 2a and 2b again. Each microstructure 20 may have a second refractive index n2 and may include a bottom surface 24, a first light-facing surface 21, a second light-facing surface 22, and a third light-facing surface 23. The first light-facing surface 21 may extend upward from one end of the bottom surface 24, and a first internal angle A is formed between the first light-facing surface 21 and the bottom surface 24. In some embodiments, the first internal angle A may be greater than or equal to 50° and less than or equal to 80°. In Figure 2a, the first internal angle A is illustrated as 70°. The second light-facing surface 22 may be connected to the end of the first light-facing surface 21 away from the end connected to the bottom surface 24 and extend upward, and a second internal angle B is formed between the second light-facing surface 22 and the first light-facing surface 21. In some embodiments, the second internal angle B may be greater than or equal to 120° and less than or equal to 175°. In Figure 2a, the second internal angle B is illustrated as 150°. One end of the third light-facing surface 23 may be connected to the end of the second light-facing surface 22 away from the first light-facing surface 21 and extend downward, and the other end of the third light-facing surface 23 may be connected to the end of the bottom surface 24 away from the first light-facing surface 21. In some embodiments, the third light-facing surface 23 has a convex arc F in the form of a free-form curve. In some embodiments, the height of each microstructure 20 may be 50 μm, and the distance between two adjacent microstructures 20 may be 50 μm, but this is not limited to this.

[0073] As shown in FIG2 a , the outer convex arcs F are arranged in a two-dimensional manner in a periodic manner, with two of them back to back.

[0074] As shown in FIG2b , at least one third interior angle C is formed between the second light-facing surface 22 and the first light-facing surface 21, so that the second light-facing surface 22 and the first light-facing surface 21 have multiple interior angles, or even form a free-form surface. In some embodiments, the third interior angle C can be greater than or equal to 120° and less than or equal to 160°.

[0075] The microstructure 20 may be made of, but is not limited to, ethylene tetrafluoroethylene (ETFE), polymethyl methacrylate (PMMA), polycarbonate (PC), or liquid optical clear resin.

[0076] The second refractive index n2 is greater than or equal to 1.30 and less than or equal to 1.49.

[0077] In some embodiments, the microstructured light-collecting film structure 100 of the present invention may further include an anti-reflective film 30. The anti-reflective film 30 may be coated on the microstructures 20. In some embodiments, the anti-reflective film 30 may have a first refractive index n1, which is less than the second refractive index n2 of each microstructure 20, and the second refractive index n2 of each microstructure 20 is less than the third refractive index n3 of the forward light-collecting optical film 10. The area outside the anti-reflective film 30 (i.e., above the anti-reflective film 30 in Figures 2a and 2b) has a refractive index n0 of air.

[0078] The anti-reflection film 30 may be, but is not limited to, anti-reflection liquid transparent optical resin (AR Optical Clear Resin).

[0079] The first refractive index n1 is greater than or equal to 1.01 and less than or equal to 1.30.

[0080] Preferably, when selecting materials during the microstructure optimization design process, n1=n0 can be selected. In this case, n2 can be selected from a self-cleaning and dust-resistant material, such as but not limited to ethylene tetrafluoroethylene (ETFE).

[0081] The positive light-collecting optical film 10 may be, but is not limited to, a liquid transparent optical adhesive (Optical Clear Resin) or an optical clear adhesive (Optical Clear Adhesive).

[0082] The third refractive index n3 is greater than or equal to 1.40 and less than or equal to 1.68.

[0083] Preferably, when selecting materials during the microstructure optimization design process, n3=n2 can be selected.

[0084] In some embodiments, the microstructured light-collecting film structure 100 of the present invention may further include an optical adhesive 40. The optical adhesive 40 may be disposed below the forward light-collecting optical film 10. The optical adhesive 40 may have a fourth refractive index n4, where the third refractive index n3 of the forward light-collecting optical film 10 is less than the fourth refractive index n4 of the optical adhesive 40.

[0085] The optical adhesive 40 may be, but is not limited to, ethylene vinyl acetate (EVA), polyolefin elastomer (POE), or co-extruded POE (EPE).

[0086] The fourth refractive index n4 is greater than or equal to 1.45 and less than or equal to 1.70.

[0087] As shown in Figures 2a to 2b and Figures 4a to 4b, in the microstructure light-collecting film structure 100 of the first embodiment of the present invention, the microstructures 20 are symmetrically arranged in an array and have a latitude position optimization function. In addition to the original sunlight incident at 0°, the sunlight L1 and L2 in large-angle directions (from 10° to 80° and 80° to 10° directions, respectively) can be expanded all day long (including spring, summer, autumn, winter, sunrise to sunset, and ambient light) to increase the efficiency of contacting sunlight, thereby achieving a truly building-integrated solar module / system (BIPV / BIPVs) that efficiently gains and collects sunlight or ambient light, thereby greatly improving the system's power generation efficiency and reducing the levelized cost of electricity (LCOE) per kilowatt-hour.

[0088] Please refer to Figures 2a to 2b and Figures 4a to 4b. The microstructure light-collecting film structure 100 of the first embodiment of the present invention can be installed on various inorganic / organic photovoltaic chips / photoelectric sensors / and their modules 200, so that the microstructure light-collecting film structure 100 of the present invention and various inorganic / organic photovoltaic chips / photoelectric sensors / and their modules 200 are integrally formed into a microstructure light-collecting solar module 300.

[0089] Figure 5 is a 3D top view of the microstructure light-collecting film structure of the present invention. Figures 6a to 6b are schematic cross-sectional views of the microstructure light-collecting film structure of the present invention installed in a direction perpendicular (orthogonal) to the ground, and according to the section line CC of Figure 5. Figures 7a to 7b are schematic top views of the multi-dimensional light-collecting structure of the second embodiment of the microstructure light-collecting film structure of the present invention arranged in a linear array. Figures 8a to 8b are schematic cross-sectional views of the microstructure light-collecting film structure of the present invention applied to a solar module, and according to the section line CC of Figure 7a. The microstructure light-collecting film structure of the second embodiment of the present invention is the same or similar to the microstructure light-collecting film structure 100 of the aforementioned first embodiment, and therefore, the same elements are represented by the same element numbers.

[0090] 5 and 6 a to 6 b , the microstructure light-collecting film structure 100 of the second embodiment of the present invention includes a forward light-collecting optical film 10 and a plurality of microstructures 20 .

[0091] Among them, when the microstructure light-collecting film structure 100 is installed vertically (orthogonally) to the ground, its installation angle can be 90°±10° or optimized for a specific angle (such as the Leaning Tower of Pisa) and it also has the light collection function in all weather conditions (including spring, summer, autumn and winter, sunrise to sunset and surrounding ambient light, etc.).

[0092] The positive light-collecting optical film 10 may have a light-collecting surface 11. In some embodiments, the positive light-collecting optical film has a third refractive index n3.

[0093] Referring to Figures 5 and 7a-7b, a plurality of microstructures 20 can be arranged in an array on the light-collecting surface 11 of the forward-light-collecting optical film 10. The difference between the array arrangement in the second embodiment and the array arrangement in the first embodiment is that the array arrangement in the second embodiment can be a linear array arrangement, including at least a circular linear array arrangement, a polygonal linear array arrangement, and a uniaxial linear array arrangement. In Figure 1, the array arrangement is a quadrilateral (offset) linear array arrangement; in Figure 3, the array arrangement is a quadrilateral (centered) linear array arrangement.

[0094] Please refer to Figures 6a and 6b again. Each microstructure 20 may have a second refractive index n2 and may include a bottom surface 24, a first light-facing surface 21, a second light-facing surface 22, and a third light-facing surface 23. The first light-facing surface 21 may extend upward from one end of the bottom surface 24, and a first internal angle A is formed between the first light-facing surface 21 and the bottom surface 24. In some embodiments, the first internal angle A may be greater than or equal to 50° and less than or equal to 80°. In Figure 6, the first internal angle A is illustrated as 70°. The second light-facing surface 22 may be connected to the end of the first light-facing surface 21 away from the end connected to the bottom surface 24 and extend upward, and a second internal angle B is formed between the second light-facing surface 22 and the first light-facing surface 21. In some embodiments, the second internal angle B may be greater than or equal to 120° and less than or equal to 175°. In Figure 6a, the second internal angle B is illustrated as 150°. One end of the third light-facing surface 23 may be connected to the end of the second light-facing surface 22 away from the first light-facing surface 21 and extend downward, and the other end of the third light-facing surface 23 may be connected to the end of the bottom surface 24 away from the first light-facing surface 21. In some embodiments, the third light-facing surface 23 has a convex arc F in the form of a free-form curve. In some embodiments, the height of each microstructure 20 may be 50 μm, and the distance between two adjacent microstructures 20 may be 50 μm, but this is not limited to this.

[0095] As shown in FIG6b , at least one third interior angle C is formed between the second light-facing surface 22 and the first light-facing surface 21, so that the second light-facing surface 22 and the first light-facing surface 21 have multiple interior angles, or even a free-form surface. In some embodiments, the third interior angle C may be greater than or equal to 120° and less than or equal to 160°.

[0096] In some embodiments, the microstructured light-collecting film structure 100 of the present invention may further include an anti-reflective film 30. The anti-reflective film 30 may be coated on the microstructures 20. In some embodiments, the anti-reflective film 30 may have a first refractive index n1, which is less than the second refractive index n2 of each microstructure 20, and the second refractive index n2 of each microstructure 20 is less than the third refractive index n3 of the forward light-collecting optical film 10. The area outside the anti-reflective film 30 (i.e., above the anti-reflective film 30 in FIG6 a ) has a refractive index n0 of air.

[0097] In some embodiments, the microstructured light-collecting film structure 100 of the present invention may further include an optical adhesive 40. The optical adhesive 40 may be disposed below the forward light-collecting optical film 10. The optical adhesive 40 may have a fourth refractive index n4, where the third refractive index n3 of the forward light-collecting optical film 10 is less than the fourth refractive index n4 of the optical adhesive 40.

[0098] As shown in Figures 6a to 6b and Figures 8a to 8b, in the microstructure light-collecting film structure 100 of the second embodiment of the present invention, the microstructures 20 are arranged in a linear array and have a latitude position optimization function. In addition to the original sunlight incident at 0°, the reception of all sunlight L3 from large angle directions (from the 80°~10° direction as shown in Figures 6a to 6b or the 80°~10° direction as shown in Figures 8a to 8b) can be expanded to increase the efficiency of contacting sunlight, thereby achieving a truly building-integrated solar module / system (BIPV / BIPVs) that efficiently gains and collects sunlight or ambient light, thereby greatly improving the system's power generation efficiency and reducing the levelized cost of electricity (LCOE) per kilowatt-hour.

[0099] As shown in FIG8b , at least one third interior angle C is formed between the second light-facing surface 22 and the first light-facing surface 21, so that the second light-facing surface 22 and the first light-facing surface 21 have multiple interior angles, or even a free-form surface. In some embodiments, the third interior angle C may be greater than or equal to 120° and less than or equal to 160°.

[0100] Please refer to Figures 6a to 6b and Figures 8a to 8b. The microstructure light-collecting film structure 100 of the second embodiment of the present invention can be installed on various inorganic / organic photovoltaic chips / photoelectric sensors / and their modules 200, so that the microstructure light-collecting film structure 100 of the present invention and various inorganic / organic photovoltaic chips / photoelectric sensors / and their modules 200 are integrally formed into a microstructure light-collecting solar module 300.

[0101] Figures 9a and 9b illustrate an embodiment of the present invention's microstructured light-collecting film structure installed (operated) in a direction perpendicular (orthogonal) to the ground. Figures 10a and 10b illustrate an embodiment of the present invention's microstructured light-collecting film structure installed (operated) in a direction perpendicular (orthogonal) to the ground in a solar module.

[0102] As shown in FIG. 9 a to FIG. 9 b and FIG. 10 a to FIG. 10 b , the microstructured light-collecting film structure of the present invention and its application in a solar module can reflect sunlight / ambient light through other buildings or the ground.

[0103] Among them, when the microstructure light-collecting film structure 100 and its application are installed in the vertical (orthogonal) ground direction of the solar module, its installation angle can be 90°±10° or optimized for a specific angle (such as the Leaning Tower of Pisa) and it also has the light collection function of all weather conditions (including spring, summer, autumn and winter, sunrise to sunset and surrounding ambient light, etc.).

[0104] Figure 11 is a graph showing the relationship between the photoelectric conversion efficiency of the microstructured light-concentrating film structure of the present invention and solar flux concentration. Referring to Figure 11, the relationship between the conversion efficiency of the microstructured light-concentrating film structure 100 of the present invention and solar flux concentration is shown. Curve a represents a vertical structure with a width of 43.6 μm and a height of 60 μm, with backside recombination of 1000 cm / s and frontside recombination of 10 cm / s (a); curve b represents the technology disclosed by Slade et al. in the prior art; curve c represents a silver cell; and curve d represents the technology disclosed by Sater et al. in the prior art. Clearly, the microstructured light-concentrating film structure 100 of the present invention (i.e., curve a) completely overcomes the complex structure and inefficient fixed-bracket design of traditional solar modules, as well as other previously disclosed related light-concentrating module technologies, significantly improving the photoelectric conversion efficiency of traditional solar modules and surpassing the power generation efficiency issues of traditional fixed-bracket solar modules. This significantly improves the system's power generation efficiency and reduces the cost per kilowatt-hour of electricity.

[0105] In summary, the microstructure light-collecting film structure 100 of the present invention and the microstructure light-collecting solar module 300 combined with various inorganic / organic photovoltaic chips / photoelectric sensors / and their modules 200, optimize the microstructure profile defined within a specific latitude range according to the facing directions of the different light-facing surfaces (i.e., the first light-facing surface 21, the second light-facing surface 22 and the third light-facing surface 23, and even optimize more light-facing surfaces to form a second free-form surface) of the microstructure 20 on the optical film (i.e., the forward light-collecting optical film 10), to collect solar energy / ambient light in a direction perpendicular to sunlight or perpendicular to the ground, thereby achieving a truly building-integrated solar module / system (BIPV / BIPVs) that efficiently collects sunlight or ambient light, thereby significantly improving the system's power generation efficiency and reducing the levelized cost of electricity (LCOE) per kilowatt-hour.

Claims

1. A microstructure light-collecting film structure, comprising: A positive light-collecting optical film having a light-collecting surface; and A plurality of microstructures are arranged in an array and disposed on the light-collecting surface of the forward light-collecting optical film, each of the microstructures comprising a bottom surface, a first light-facing surface, a second light-facing surface and a third light-facing surface, the first light-facing surface extending upward from one end of the bottom surface, and a first inner angle is formed between the first light-facing surface and the bottom surface, the second light-facing surface is connected to an end of the first light-facing surface away from the bottom surface and extends upward, and a second inner angle is formed between the second light-facing surface and the first light-facing surface, one end of the third light-facing surface is connected to an end of the second light-facing surface away from the first light-facing surface and extends downward, and the other end of the third light-facing surface is connected to an end of the bottom surface away from the first light-facing surface.

2. The microstructure light-collecting film structure as claimed in claim 1, wherein: The third light-facing surface has an outward convex arc in the form of a free-curved surface. 3 . The microstructure light-collecting film structure as claimed in claim 2 , further comprising an anti-reflection film coated on the microstructures, and the anti-reflection film has a first refractive index n1 .

4. The microstructure light-collecting film structure as claimed in claim 3, wherein: Each of the microstructures has a second refractive index n2, and the first refractive index n1 is smaller than the second refractive index n2.

5. The microstructure light-collecting film structure as claimed in claim 4, wherein: The forward light-collecting optical film has a third refractive index n3, and the second refractive index n2 is smaller than the third refractive index n3. 6 . The microstructure light-collecting film structure as claimed in claim 5 , further comprising an optical adhesive disposed below the forward light-collecting optical film, wherein the optical adhesive has a fourth refractive index n4 , and the third refractive index n3 is smaller than the fourth refractive index n4 .

7. The microstructure light-collecting film structure as claimed in claim 1, wherein: The first interior angle is greater than or equal to 50° and less than or equal to 80°.

8. The microstructure light-collecting film structure as claimed in claim 7, wherein: The second interior angle is greater than or equal to 120° and less than or equal to 175°; and at least one third interior angle is formed between the second light-facing surface and the first light-facing surface, and the third interior angle is greater than or equal to 130° and less than or equal to 160°.

9. The microstructure light-collecting film structure as claimed in claim 1, wherein: The array arrangement is an array symmetrical arrangement, including but not limited to a circular array symmetrical arrangement, a polygonal array symmetrical arrangement and a single-axis array symmetrical arrangement.

10. The microstructure light-collecting film structure as claimed in claim 1, wherein: The array arrangement is a linear array arrangement, including but not limited to a circular linear array arrangement, a polygonal linear array arrangement and a single-axis linear array arrangement.

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