Optical film assembly and optical system

Abstract

An optical system includes an optical film assembly, a light source to emit light having at least first through fifth wavelengths, a first light receiving area disposed on a second, opposite a first major side of the optical film assembly, and spaced apart second and third light receiving areas disposed on the first major side of the optical film assembly. The optical film assembly receives the emitted light and transmits at least 50% of the received emitted light for each of the first and third wavelengths and reflects at least 50% of the received emitted light for each of the second, fourth, and fifth wavelengths, the first light receiving area receiving the transmitted light having the first and third wavelengths, the second light receiving area receiving the reflected light having the second and fourth wavelengths, and the third light receiving area receiving the reflected light having the fifth wavelength.

Description

OPTICAL FILM ASSEMBLY AND OPTICAL SYSTEMTechnical Field

[0001] The present disclosure relates to an optical film assembly and an optical system including the optical film assembly.Background

[0002] There is always a need for effective utilization of energy. For example, in case of use of a light source as an energy source, effective reception and utilization of emitted light of the light source is important for better productivity.Summary

[0003] In a first aspect, the present disclosure provides an optical system. The optical system includes an optical film assembly and a light source. The optical film assembly includes a plurality of polymeric layers numbering at least 10 in total. Each of the polymeric layers has an average thickness of less than about 500 nanometers (nm). The light source is disposed on a first major side of the optical film assembly. The light source is configured to emit light having at least first through fifth sequentially increasing wavelengths. Each of the wavelengths in the sequence of the at least five wavelengths is greater than the smaller wavelengths in the sequence by at least 10 nm. The first through the third wavelengths are visible wavelengths in a visible wavelength range extending from about 420 nm to about 680 nm. The second wavelength is a green wavelength within a green wavelength range extending from about 500 nm to about 560 nm. The fourth and fifth wavelengths are infrared wavelengths in an infrared wavelength range extending from about 700 nm to about 2500 nm. The optical system further includes a first light receiving area disposed on a second, opposite the first, major side of the optical film assembly. The optical system further includes spaced apart second and third light receiving areas disposed on the first major side of the optical film assembly. The optical film assembly is configured to receive the emitted light from the light source and transmit at least 50% of the received emitted light for each of the first and third wavelengths and reflect at least 50% of the received emitted light for each of the second, fourth, and fifth wavelengths. The first light receiving area receives the transmitted light having the first and third wavelengths, the second light receiving area receives the reflected light having the second and fourth, but not the fifth, wavelengths, and the third light receiving area receives the reflected light having the fifth, but not the second or the fourth, wavelengths.

[0004] In a second aspect, the present disclosure provides an optical film assembly. The optical film assembly includes first and second optical films forming a first inclusion angle of between about 15 degrees and about 80 degrees therebetween. Each of the first and second optical films includes aplurality of polymeric layers numbering at least 10 in total. Each of the polymeric layers has an average thickness of less than about 500 nm. For a substantially collimated incident light, for a first incident angle of less than about 10 degrees for each of the first and second optical films, and for at least one polarization state, a ratio of an optical transmittance of the second optical film to an optical transmittance of the first optical film is greater than about 1.5 for at least a first green wavelength within a green wavelength range extending from about 500 nm to about 560 nm. For a substantially collimated light incident on the first optical film at the first incident angle with the first optical film disposed between the second optical film and the incident light, for a first infrared wavelength range extending from about 740 nm to about 1040 nm, and for the at least one polarization state, the first and second optical films of the optical film assembly, in combination, have an average optical transmittance of less than about 20%. Further, reducing the first inclusion angle to less than about 10 degrees, increases an optical transmittance of the first and second optical films of the optical film assembly, in combination, by at least 10% for at least a first intermediary infrared wavelength in an intermediary infrared wavelength range extending from about 1040 nm to about 1700 nm.

[0005] In a third aspect, the present disclosure provides an optical film assembly. The optical film assembly includes first and second optical films forming a first inclusion angle of greater than about 5 degrees therebetween. Each of the first and second optical fdms includes a plurality of polymeric layers numbering at least 10 in total. Each of the polymeric layers has an average thickness of less than about 500 nm. For a substantially collimated light incident on the first optical film of the optical film assembly at a first incident angle of less than about 10 degrees with the first optical film disposed between the second optical film and the incident light, for an infrared wavelength range that extends from at most about 1000 nm to at least about 1300 nm, and for at least one polarization state, the first and second optical films of the optical film assembly, in combination, have an average optical transmittance of less than about 15% and a maximum optical transmittance of less than about 20% when the first inclusion angle is greater than about 20 degrees. When the first inclusion angle is reduced to less than about 10 degrees, then a plot of an optical transmittance of the first and second optical films of the optical film assembly, in combination, as a function of wavelength includes a global peak of greater than about 20% in the infrared wavelength range with a corresponding full width at half maximum of greater than about 10 nm.

[0006] In a fourth aspect, the present disclosure provides an optical film assembly. The optical film assembly includes first and second optical films forming a first inclusion angle of greater than about 20 degrees therebetween. Each of the first and second optical films includes a plurality of polymeric layers numbering at least 10 in total. Each of the polymeric layers has an average thickness of less than about 500 nm. For a substantially collimated light incident on the first optical film of the optical film assembly at a first incident angle of less than about 10 degrees with the first optical film disposed between the second optical film and the incident light, and for at least one polarization state, an optical transmittance of the first and second optical films of the optical film assembly, incombination, versus wavelength in a wavelength range of interest extending from about 400 nm to about 1700, includes a plurality of alternating high transmittance and high reflectance continuous wavelength regions. Each of the continuous wavelength regions is at least 20 nm wide. Each of the high transmittance continuous wavelength regions has an average optical transmittance of at least 40%. Each of the high reflectance continuous wavelength regions has an average optical reflectance of at least 40%. A first one of the high reflectance continuous wavelength regions includes a green wavelength disposed in a green wavelength range extending from about 510 nm to about 600 nm, and a second one of the high reflectance continuous wavelength regions includes an infrared wavelength disposed in an infrared wavelength range extending from about 750 nm to about 1700 nm. The first and second optical films of the optical film assembly, in combination, have an optical transmittance of less than about 20% at the infrared wavelength, and when the first inclusion angle is reduced to less than about 10 degrees, the optical transmittance of the first and second optical films of the optical fdm assembly, in combination, increases at the infrared wavelength by at least 5%.

[0007] In a fifth aspect, the present disclosure provides an optical film assembly. The optical film assembly includes first and second optical films forming a first inclusion angle of greater than about 20 degrees therebetween. Each of the first and second optical films includes a plurality of polymeric layers numbering at least 10 in total. Each of the polymeric layers has an average thickness of less than about 500 nm. For a substantially collimated light incident on the first optical film of the optical film assembly at a first incident angle of less than about 10 degrees with the first optical film disposed between the second optical film and the incident light, an optical transmittance of the first and second optical films of the optical film assembly, in combination, versus wavelength includes a high reflectance continuous green wavelength region disposed between high transmittance continuous blue and red wavelength regions in a continuous visible wavelength range extending from about 420 nm to about 680 nm. Each of the continuous wavelength regions is at least 20 nm wide. Each of the high transmittance continuous wavelength regions has an average optical transmittance of at least 40%. Each of the high reflectance continuous wavelength regions has an average optical reflectance of at least 40%. The first inclusion angle is sufficiently large so that a maximum optical transmittance of the first and second optical films of the optical film assembly, in combination, in a continuous first infrared wavelength range extending from about 750 nm to about 1500 nm is less than about 20%.

[0008] The details of one or more examples of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.Brief Description of the Drawings

[0009] Exemplary embodiments disclosed herein may be more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components.However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.

[0010] FIG. 1 shows a schematic view of an optical system, according to an embodiment of the present disclosure;

[0011] FIG. 2A shows a detailed schematic view of first and second optical films of an optical film assembly of the optical system of FIG. 1, according to an embodiment of the present disclosure;

[0012] FIG. 2B shows a schematic view of the first and second optical films of the optical film assembly, according to an embodiment of the present disclosure;

[0013] FIG. 3 A shows a graph depicting variations in optical transmittances of the first and second optical films for a substantially collimated incident light incident on the first and second optical films at different incident angles, according to an embodiment of the present disclosure;

[0014] FIG. 3B shows a magnified graph including some of curves of the graph of FIG. 3 A, according to an embodiment of the present disclosure;

[0015] FIG. 4A shows a graph depicting variations in optical transmittances of the first and second optical films, in combination, for a substantially collimated light incident on the first optical film and different first inclusion angles, according to an embodiment of the present disclosure;

[0016] FIG. 4B shows a magnified graph of the graph shown in FIG. 4A, according to an embodiment of the present disclosure; and

[0017] FIG. 5 shows a graph including some of curves of the graph of FIG. 4A, according to an embodiment of the present disclosure.Detailed Description

[0018] In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

[0019] In the following disclosure, the following definitions are adopted.

[0020] As used herein, all numbers should be considered modified by the term “about”. As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably.

[0021] As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within + / - 20 % for quantifiable properties).

[0022] The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0023] The term “about”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 5% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0024] As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be construed as limiting of this disclosure. The terms “first” and “second” when used in conjunction with a feature or an element can be interchanged throughout the embodiments of this disclosure.

[0025] As used herein, “at least one of A and B” should be understood to mean “only A, only B, or both A and B”.

[0026] Effective utilization of energy is need of an hour. For example, if a light source is used as an energy source, effective reception, and utilization of emitted light from the light source is important for better productivity. Nowadays, use of greenhouses for food production is on a rise due to climate change trends. Greenhouse operations can be energy intensive, and profitability is highly dependent on maintaining high crop yield and minimizing energy use.

[0027] The present disclosure relates to an optical film assembly. The present disclosure further relates to an optical system including the optical film assembly.

[0028] The optical film system includes the optical film assembly having a plurality of polymeric layers numbering at least 10 in total. Each of the polymeric layers has an average thickness of less than about 500 nanometers (nm). The light source is disposed on a first major side of the optical film assembly. The light source is configured to emit light having at least first through fifth sequentially increasing wavelengths. Each of the wavelengths in the sequence of the at least five wavelengths is greater than the smaller wavelengths in the sequence by at least 10 nm. The first through the third wavelengths are visible wavelengths in a visible wavelength range extending from about 420 nm to about 680 nm. The second wavelength is a green wavelength within a green wavelength range extending from about 500 nm to about 560 nm. The fourth and fifth wavelengths are infrared wavelengths in an infrared wavelength range extending from about 700 nm to about 2500 nm. The optical system further includes a first light receiving area disposed on a second, opposite the first, major side of the optical film assembly. The optical system further includes spaced apart second and third light receiving areas disposed on the first major side of the optical film assembly. The optical film assembly is configured to receive the emitted light from the light source and transmit at least 50% of the received emitted light for each of the first and third wavelengths and reflect at least 50% of the received emitted light for each of the second, fourth, and fifth wavelengths. The first light receiving area receives the transmitted light having the first and third wavelengths, the second light receiving area receives the reflected light having the second and fourth, but not the fifth, wavelengths, and the third light receiving area receives the reflected light having the fifth, but not the second or the fourth wavelengths.

[0029] The optical system including the optical film assembly may be configured to partially transmit and partially reflect the received emitted light from the light source. Specifically, the emitted light having the first and third wavelengths is substantially transmitted through the optical film assembly to the first light receiving area, and the emitted light having the second, fourth, and fifth wavelengths is substantially reflected from the optical film assembly to the second and third light receiving areas. Hence, the first through fifth wavelengths of the emitted light may be received in either the first light receiving area, the second light receiving area, or the third light receiving area depending upon where they can be effectively utilized. For instance, the emitted light having the first and third wavelengths may be used in food production in a greenhouse setup, and the emitted light having the second, fourth, and fifth wavelengths may be used in generating electricity. In addition, the generated electricity may be utilized for operations of the greenhouse setup. Hence, such optical system may reduce costs of the greenhouse setup and may also generate less carbon footprints. The second, fourth, and fifth wavelengths may optionally be used as a heat source.

[0030] Referring now to figures, FIG. 1 is a schematic view of an optical system 300, according to an embodiment of the present disclosure.

[0031] The optical system 300 includes an optical film assembly 200. The optical film assembly200 has a first major side 201 and a second major side 202, opposite the first major side 201. In the illustrated embodiment of FIG. 1, the optical film assembly 200 includes first and second optical films 10, 20.

[0032] In some embodiments, the first and second optical films 10, 20 form a first inclusion angle al of between about 15 degrees and about 80 degrees therebetween. In some embodiments, the first and second optical films 10, 20 form the first inclusion angle al of between about 20 degrees and about 70 degrees, about 20 degrees and about 60 degrees, or about 25 degrees and about 50 degrees therebetween.

[0033] In some embodiments, the optical film assembly 200 includes the first and second optical films 10, 20 forming the first inclusion angle al of greater than about 5 degrees therebetween. In some embodiments, the optical film assembly 200 includes the first and second optical films 10, 20 forming the first inclusion angle al of greater than about 10 degrees, greater than about 15, greater than about 20 degrees, greater than about 25 degrees, greater than about 30 degrees, greater than about 35 degrees, or greater than about 40 degrees therebetween.

[0034] The optical system 300 further includes a light source 30 disposed on the first major side201 of the optical film assembly 200. The light source 30 is configured to emit light 40.

[0035] The optical system 300 further includes a first light receiving area 50 disposed on the second major side 202, opposite the first major side 201, of the optical film assembly 200. In some embodiments, the first light receiving area 50 includes one or more plants. In some embodiments, the first light receiving area 50 may be disposed inside a greenhouse.

[0036] The optical system 300 further includes spaced apart second and third light receiving areas 51, 52 disposed on the first major side 201 of the optical film assembly 200. Specifically, the optical system 300 includes the second light receiving area 51 disposed on the first major side 201 and the third light receiving area 52 spaced apart from the second light receiving area 51 and disposed on the first major side 201 of the optical film assembly 200. In some embodiments, at least one of the second and third light receiving areas 51, 52 includes one or more optical detectors configured to convert at least a portion of an incident light to electricity or heat. In some embodiments, at least one of the second and third light receiving areas 51, 52 includes a photothermal or a second photovoltaic system. Specifically, in some embodiments, at least one of the second and third light receiving areas 51, 52 includes the photothermal system configured to convert at least the portion of the incident light to heat. Further, in some embodiments, at least one of the second and third light receiving areas 51, 52 includes the second photovoltaic system configured to convert at least the portion of the incident light to electricity.

[0037] FIG. 2A is a detailed sectional view of the first and second optical films 10, 20, according to an embodiment of the present disclosure.

[0038] Each of the first and second optical films 10, 20 defines mutually orthogonal x, y, and z- axes. The x and y-axes are in-plane axes of each of the first and second optical films 10, 20, while the z-axis is a transverse axis disposed along a thickness of each of the first and second optical films 10,20. In other words, the x and y-axes are disposed along a plane of each of the first and second optical films 10, 20, while the z-axis is perpendicular to the plane of each of the first and second optical films10, 20.

[0039] The optical film assembly 200 includes a plurality of polymeric layers 11, 12, 21, 22. Specifically, each of the first and second optical films 10, 20 includes the plurality of polymeric layers11, 12, 21, 22. More specifically, the first optical fdm 10 includes the plurality of polymeric layers 11, 12 and the second optical film 20 includes the plurality of polymeric layers 21, 22. The plurality of polymeric layers 11, 12, 21, 22 numbers at least 10 in total. Specifically, each of the first and second optical films 10, 20 includes the plurality of polymeric layers 11, 12, 21, 22 numbering at least 10 in total. In some embodiments, the plurality of polymeric layers 11, 12, 21, 22 numbers at least 20, at least 50, at least 75, at least 100, at least 150, at least 200, at least 250, at least 300, at least 400, or at least 500 in total.

[0040] Each of the polymeric layers 11, 12, 21, 22 has an average thickness t of less than about 500 nanometers (nm). The term “average thickness t”, as used herein, refers to an average of thicknesses measured at multiple points across a plane (i.e., a x-y plane) of each of the first and second polymeric layers 11, 12, 21, 22. In some embodiments, each of the polymeric layers 11, 12,21, 22 has the average thickness t of less than about 450 nm, less than about 400 nm, less than about 350 nm, less than about 300 nm, less than about 250 nm, or less than about 200 nm.

[0041] In some embodiments, the polymeric layers 11, 12, 21, 22 of the first and second optical films 10, 20 are disposed between a pair of skin layers 16, 26. Specifically, the polymeric layers 11, 12 of the first optical film 10 are disposed between the pair of skin layers 16, and the polymeric layers 21, 22 of the second optical films 20 are disposed between the pair of skin layers 26. Each of the pair of skin layers 16, 26 may have an average thickness st. The term “the average thickness st”, as used herein, refers to an average of thicknesses measured at multiple points across a plane (i.e., the x-y plane) of each of the pair of skin layer 16, 26.

[0042] In some embodiments, the pair of skin layers 16, 26 may protect the first and second optical films 10, 20 and may also provide mechanical stability to the first and second optical films 10, 20. In some cases, the pair of skin layers 16, 26 may act as protective boundary layers (PBLs). In some embodiments, the polymeric layers 11, 12, 21, 22 of the first and second optical films 10, 20 and the pair of skin layers 16, 26 are further disposed between one or more additional layers. The one or more additional layers may further act as the PBLs.

[0043] FIG. 2B is a schematic view of the first and second optical films 10, 20 of the optical film assembly 200, according to an embodiment of the present disclosure. FIG. 2B further shows a substantially collimated incident light 46 incident on the first and second optical films 10, 20 at a first incident angle bl and at a second incident angle b2. In some embodiments, the first incident angle bl is less than the second incident angle b2.

[0044] In some embodiments, the first incident angle bl is less than about 10 degrees. In some embodiments, the first incident angle b 1 is less than about 8 degrees, less than about 6 degrees, less than about 4 degrees, less than about 2 degrees, or less than about 1 degree. In some embodiments, the first incident angle bl is about 0 degree.

[0045] In some embodiments, the second incident angle b2 is greater than about 25 degrees. In some embodiments, the second incident angle b2 is greater than about 30 degrees, greater than about 35 degrees, greater than about 40 degrees, greater than about 45 degrees, or greater than about 50 degrees. In some embodiments, the second incident angle b2 is about 40 degrees.

[0046] FIG. 3 A is a graph 301 depicting variations in optical transmittances of the first and second optical films 10, 20 for the substantially collimated incident light 46 (shown in FIG. 2B) incident on the first and second optical films 10, 20 at different incident angles.

[0047] Wavelength is expressed in nanometers (nm) in the abscissa. The optical transmittance is expressed as a transmittance percentage (%) in the ordinate.

[0048] The graph 301 includes curves 302, 304, 306, 308, and 310 depicting the optical transmittances of the first optical film 10 for the substantially collimated incident light 46 incident at the different incident angles.

[0049] Specifically, the curve 302 depicts the optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at 0 about degree, the curve 304 depicts the optical transmittance of the first optical film 10 for the substantially collimated incident light 46incident at about 10 degrees, the curve 306 depicts the optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at about 20 degrees, the curve 308 depicts the optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at about 30 degrees, and the curve 310 depicts the optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at about 40 degrees.

[0050] The graph 301 further includes curves 322, 324, 326, 328, and 330 depicting the optical transmittances of the second optical film 20 for the substantially collimated incident light 46 incident at the different incident angles.

[0051] Specifically, the curve 322 depicts the optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at about 0 degree, the curve 324 depicts the optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at about 10 degrees, the curve 326 depicts the optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at about 20 degrees, the curve 328 depicts the optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at about 30 degrees, and the curve 330 depicts the optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at about 40 degrees.

[0052] Table 1 provided below summarizes average optical transmittances (in percentage) of the first and second optical films 10, 20 for the substantially collimated incident light 46 incident at the different incident angles for different wavelength regions.Table 1where, OP 1(0) refers to the average optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 0 degree;OP 1(10) refers to the average optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 10 degrees;OP 1(20) refers to the average optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 20 degrees;OP 1(30) refers to the average optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 30 degrees;OP 1(40) refers to the average optical transmittance of the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 40 degrees;OP2(0) refers to the average optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at the incident angle of about 0 degree;OP2(10) refers to the average optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at the incident angle of about 10 degrees;OP2(20) refers to the average optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at the incident angle of about 20 degrees;OP2(30) refers to the average optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at the incident angle of about 30 degrees; andOP2(40) refers to the average optical transmittance of the second optical film 20 for the substantially collimated incident light 46 incident at the incident angle of about 40 degrees.

[0053] FIG. 3B is a graph 350 depicting variations in the optical transmittances of the first and second optical films 10, 20 for the substantially collimated incident light 46 incident at the incident angles of about 0 degree and about 40 degrees, according to an embodiment of the present disclosure. Specifically, FIG. 3B shows a magnified version of the graph 301 of FIG. 3A. Further, the graph 350 includes only the curves 302, 310, 322, and 330.

[0054] Referring to FIGS. 1 to 3A-3B, as discussed above, the light source 30 is configured to emit the light 40. The emitted light 40 has at least first through fifth sequentially increasing wavelengths Fl, F2, F3, F4, F5. In some embodiments, the light source 30 has an intensity spectrum substantially similar to a solar spectrum 120 (shown in FIG. 4A) at least in a continuous wavelength range extending from about 400 nm to about 2500 nm.

[0055] Further, each of the wavelengths in the sequence of the at least five wavelengths F1-F5 is greater than the smaller wavelengths in the sequence by at least 10 nm. In some embodiments, each of the wavelengths in the sequence of the at least five wavelengths F1-F5 is greater than the smaller wavelengths in the sequence by at least 15 nm, at least 20 nm, at least 25 nm, or at least 30 nm.

[0056] The first through the third wavelengths Fl, F2, F3 are visible wavelengths in a visible wavelength range extending from about 420 nm to about 680 nm. The second wavelength F2 is a green wavelength within a green wavelength range extending from about 500 nm to about 560 nm. The fourth and fifth wavelengths F4, F5 are infrared wavelengths in an infrared wavelength range extending from about 700 nm to about 2500 nm.

[0057] As shown in FIG. 1, the light 40 emitted from the light source 30 is incident on the first optical film 10 at a first angle 01 and is incident on the second optical film 20 at a second angle 02.

[0058] It is to be noted that the first angle 01 may be equal to about the first incident angle b 1 (shown in FIG. 2B) and may be interchangeably referred to as “the first incident angle 01”. Further, a magnitude of difference between the first and second angles 01, 02 may correspond the first inclusion angle al between the first and second optical films 10, 20. Furthermore, the emitted light 40 may be asubstantially collimated light and interchangeably referred to as “the substantially collimated light 40”.

[0059] Referring to FIGS. 1 to 3B, as is apparent from the graphs 301, 350, for the substantially collimated incident light 46, for the first incident angle bl of less than about 10 degrees for each of the first and second optical films 10, 20, for at least one polarization state, and continuous blue, green, and red wavelength ranges Wl, W2, W3 extending continuously respectively from about 400 nm to about 480 nm, from about 510 nm to about 600 nm, and from about 640 nm to about 680 nm, each of the first and second optical films 10, 20 has the average optical transmittance of greater than about 50% in each of the blue and red wavelength ranges Wl, W3, the first optical film 10 has the average optical transmittance of less than about 20% in the green wavelength range W2, and the second optical film 20 has the average optical transmittance of greater than about 50% in the green wavelength range W2.

[0060] In some embodiments, the at least one polarization state includes at least one of mutually orthogonal first and second polarization states. In some embodiments, the at least one polarization state includes an s-polarization state. In some embodiments, the at least one polarization state includes a p-polarization state.

[0061] In some embodiments, for the substantially collimated incident light 46, for the first incident angle bl of less than about 10 degrees for each of the first and second optical films 10, 20, for the at least one polarization state, and the continuous blue, green, and red wavelength ranges Wl, W2, W3, each of the first and second optical films 10, 20 has the average optical transmittance of greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, or greater than about 85% in each of the blue and red wavelength ranges Wl, W3, the first optical film 10 has the average optical transmittance of less than about 15%, less than about 10%, or less than about 5% in the green wavelength range W2, and the second optical film 20 has the average optical transmittance of greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, or greater than about 85% in the green wavelength range W2.

[0062] As is apparent from the curves 302, 322 and Table 1, in some embodiments, for the substantially collimated incident light 46, for the first incident angle bl of about 0 degree for each of the first and second optical films 10, 20, for the at least one polarization state and the continuous blue, green, and red wavelength ranges Wl, W2, W3, each of the first and second optical films 10, 20 has the average optical transmittance of greater than about 50% in each of the blue and red wavelength ranges Wl, W3, the first optical film 10 has the average optical transmittance of about 2.2% in the green wavelength range W2, and the second optical film 20 has the average optical transmittance of about 81.4% in the green wavelength range W2.

[0063] Further, as is apparent from the graphs 301, 350, in some embodiments, for the substantially collimated incident light 46, for the second incident angle b2 of greater than about 25degrees for each of the first and second optical films 10, 20, for the at least one polarization state, and the continuous blue, green, and red wavelength ranges Wl, W2, W3, the first optical film 10 has the average optical transmittances of less than about 70%, less than about 50%, and less than about 20% in the respective blue, green, and red wavelength ranges Wl, W2, W3, and the second optical film 20 has the average optical transmittance of greater than about 50% in each of the blue, green, and red wavelength ranges Wl, W2, W3.

[0064] Specifically, in some embodiments, for the substantially collimated incident light 46, for the second incident angle b2 of greater than about 25 degrees for each of the first and second optical films 10, 20, for the at least one polarization state, and the continuous blue, green, and red wavelength ranges Wl, W2, W3, the first optical film 10 has the average optical transmittances of less than about 70% in the blue wavelength range Wl, less than about 50% in the green wavelength range W2, and less than about 20% in the red wavelength range W3, and the second optical film 20 has the average optical transmittance of greater than about 50% in each of the blue, green, and red wavelength ranges Wl, W2, W3.

[0065] In some embodiments, for the substantially collimated incident light 46, for the second incident angle b2 for each of the first and second optical films 10, 20, for the at least one polarization state, and the continuous blue, green, and red wavelength ranges Wl, W2, W3, the first optical film 10 has the average optical transmittances of less than about 65%, less than about 60%, less than about 55%, less than about 50%, less than about 45%, or less than about 40% in the blue wavelength range Wl, less than about 45%, less than about 40%, less than about 35%, less than about 30%, less than about 25%, or less than about 20% in the green wavelength range W2, and less than about 15%, less than about 10%, or less than about 5% in the red wavelength range W3, and the second optical film 20 has the average optical transmittance of greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, greater than about 85%, or greater than about 90% in each of the blue, green, and red wavelength ranges Wl, W2, W3.

[0066] As is apparent from the curves 310, 330, and Table 1, in some embodiments, for the substantially collimated incident light 46, for the second incident angle b2 of about 40 degrees for each of the first and second optical films 10, 20, for the at least one polarization state, and the continuous blue, green, and red wavelength ranges Wl, W2, W3, the first optical film 10 has the average optical transmittance of about 48.7% in the blue wavelength range Wl, about 25.5% in the green wavelength range W2, and about 4.5% in the red wavelength range W3, and the second optical film 20 has the average optical transmittance of about 72.6% in the blue wavelength range W 1, about 78.3% in the green wavelength range W2, and about 79.4% in the red wavelength range W3.

[0067] As is apparent from the graphs 301, 350, in some embodiments, for the substantially collimated incident light 46, for each of the first incident angle bl of less than about 10 degrees for each of the first and second optical films 10, 20, and the second incident angle b2 of greater thanabout 25 degrees for each of the first and second optical films 10, 20, for the at least one polarization state, and continuous first and second infrared wavelength ranges W4, W5 extending continuously respectively from about 740 nm to about 1040 nm and from about 1200 nm to about 1700 nm, the first optical film 10 has the average optical transmittance of less than about 25% in the first infrared wavelength range W4 and the average optical transmittance of greater than about 60% in the second infrared wavelength range W5, and the second optical film 20 has the average optical transmittance of greater than about 60% in the first infrared wavelength range W4 and the average optical transmittance of less than about 25% in the second infrared wavelength range W5.

[0068] In some embodiments, for the substantially collimated incident light 46, for each of the first incident angle bl for each of the first and second optical films 10, 20, and the second incident angle b2 for each of the first and second optical films 10, 20, for the at least one polarization state, and the continuous first and second infrared wavelength ranges W4, W5, the first optical film 10 has the average optical transmittance of less than about 20%, less than about 15%, less than about 10%, or less than about 5% in the first infrared wavelength range W4 and the average optical transmittance of greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, greater than about 85%, or greater than about 90% in the second infrared wavelength range W5, and the second optical film 20 has the average optical transmittance of greater than about 65%, greater than about 70%, greater than about 75%, greater than about 80%, greater than about 85%, or greater than about 90% in the first infrared wavelength range W4 and the average optical transmittance of less than about 20%, less than about 15%, less than about 10%, or less than about 5% in the second infrared wavelength range W5.

[0069] As is apparent from the curves 302, 322, 310, 330, and Table 1, in some embodiments, for the substantially collimated incident light 46, for each of the first incident angle bl of about 0 degree for each of the first and second optical films 10, 20, and the second incident angle b2 of about 40 degrees for each of the first and second optical films 10, 20, for the at least one polarization state, and the continuous first and second infrared wavelength ranges W4, W5, the first optical film 10 has the average optical transmittance of about 7.8% for the first incident angle bl and about 13.3 % for the second incident angle b2 in the first infrared wavelength range W4 and the average optical transmittance of about 88.5% for the first incident angle bl and 87.5% for the second incident angle b2 in the second infrared wavelength range W5, and the second optical film 20 has the average optical transmittance of about 86.1% for the first incident angle bl and about 79.3% for the second incident angle b2 in the first infrared wavelength range W4, and the average optical transmittance of about 3.7% for the first incident angle b 1 and about 7.3% for the second incident angle b2 in the second infrared wavelength range W5.

[0070] FIG. 4A is a graph 400 depicting variations in optical transmittances OP1*OP2 of the first and second optical films 10, 20, in combination, for the substantially collimated light 40 (shown in FIG. 1) incident on the first optical film 10 (shown in FIG. 1) and different first inclusion angles al(shown in FIG. 1), according to an embodiment of the present disclosure. FIG. 4A also shows the solar spectrum 120.

[0071] Wavelength is expressed in nanometers (nm) in the abscissa. The optical transmittance is expressed as a transmittance percentage (%) in the left ordinate, while a solar irradiance of the solar spectrum 120 is expressed in watts per square meter per nm (W / m2 / nm) in the right ordinate.

[0072] Referring to FIGS. 1 to 4A, the graph 400 includes curves 402, 404, 406, and 408 depicting the optical transmittances OP OP2 of the first and second optical films 10, 20, in combination, for the substantially collimated light 40 and for the different first inclusion angles al.

[0073] Specifically, the curve 402 depicts the optical transmittance OP POP2 of the first and second optical films 10, 20, in combination, for the substantially collimated light 40 incident at about 0 degree and the first inclusion angle alof about 0 degree, the curve 404 depicts the optical transmittance OPPOP2 of the first and second optical films 10, 20, in combination, for the substantially collimated light 40 incident at about 0 degree on the first optical film 10 and the first inclusion angle alof about 20 degrees, the curve 406 depicts the optical transmittance OPPOP2 of the first and second optical films 10, 20, in combination, for the substantially collimated light 40 incident at about 0 degree on the first optical film 10 and the first inclusion angle alof about 30 degrees, the curve 408 depicts the optical transmittance OP POP2 of the first and second optical films 10, 20, in combination, for the substantially collimated light 40 incident at about 0 degree on the first optical film 10 and the first inclusion angle alof about 40 degrees.

[0074] Referring to FIGS. 1 to 4A, as is apparent from the graph 400, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of less than about 10 degrees with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W4 extending from about 740 nm to about 1040 nm, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have an average optical transmittance that remains less than about 20% as the first inclusion angle al is reduced to about zero.

[0075] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W4, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance that remains less than about 17.5%, less than about 15%, less than about 12.5%, less than about 10%, or less than about 7.5% as the first inclusion angle al is reduced to about zero.

[0076] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of about 0 degree with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W4, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the averageoptical transmittance that remains about 6.3% for the first inclusion angle al of about 40 degrees, about 6.6% for the first inclusion angle al of about 30 degrees, about 6.7% for the first inclusion angle al of about 20 degrees, and about 6.7% for the first inclusion angle al of about 0 degree.

[0077] Further, as is apparent from the graph 400, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of less than about 10 degrees with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W5 extending from about 1200 nm to about 1700 nm, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance that remains less than about 20% as the first inclusion angle al is reduced to about zero.

[0078] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W5, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance that remains less than about 17.5%, less than about 15%, less than about 12.5%, less than about 10%, less than about 7.5%, less than about 5%, or less than about 2.5% as the first inclusion angle al is reduced to about zero.

[0079] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of about 0 degree with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W5, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance that remains about 6.5% for the first inclusion angle al of about 40 degrees, about 3.2% for the first inclusion angle al of about 30 degrees, about 2.8% for the first inclusion angle al of about 20 degrees, and about 3.3% for the first inclusion angle al of about 0 degree.

[0080] In addition, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of less than about 10 degrees with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the green wavelength range W2, for the red wavelength range W3, and for the at least one polarization state, and as the first inclusion angle al is reduced to about zero, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance that remains less than about 20% in the green wavelength range W2 and remains greater than about 50% in the red wavelength range W3.

[0081] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the green wavelength range W2, for the red wavelength range W3, and for the at least one polarization state, and as the first inclusion angle al is reduced to about zero, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have theaverage optical transmittance that remains less than about 17.5%, less than about 15%, less than about 12.5%, less than about 10%, less than about 7.5%, less than about 5%, or less than about 2.5% in the green wavelength range W2 and remains greater than about 55%, greater than about 60%, greater than about 65%, greater than about 70%, or greater than about 75% in the red wavelength range W3.

[0082] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of about 0 degree with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the green wavelength range W2, for the red wavelength range W3, and for the at least one polarization state, and as the first inclusion angle al is reduced to about zero, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance that remains about 6.5% for the first inclusion angle al of about 40 degrees, about 3.2% for the first inclusion angle al of about 30 degrees, about 2.8% for the first inclusion angle al of about 20 degrees, and about 3.3% for the first inclusion angle al of about 0 degree in the green wavelength range W2 and remains about 62.7% for the first inclusion angle al of about 40 degrees, about 66.1% for the first inclusion angle al of about 30 degrees, about 67.4% for the first inclusion angle al of about 20 degrees, and about 68% for the first inclusion angle al of about 0 degree in the red wavelength range W3.

[0083] Moreover, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of less than about 10 degrees with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the at least one polarization state, and as the first inclusion angle al is reduced to about zero, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance that remains greater than about 40% in the blue wavelength range Wl.

[0084] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of less than about 10 degrees with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the at least one polarization state, and as the first inclusion angle al is reduced to about zero, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance that remains greater than about 45%, greater than about 50%, greater than about 55%, greater than about 60%, greater than about 65%, or greater than about 70% in the blue wavelength range W 1.

[0085] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 of about 0 degree with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance of about 61.3% for the first inclusion angle al of about 40 degrees, about 62.7% for the first inclusion angle al of about 30 degrees, about 63.9% for the first inclusion angle al of about 20 degrees, and about 65% for the first inclusion angle al of about 0 degree, in the blue wavelength range Wl.

[0086] Table 2 provided below summarizes the average of the optical transmittances OP POP2 of the first and second optical fdms 10, 20, of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10, and the different first inclusion angles al for the different wavelength regions.Table 2where, OP1(0)*OP2(0) refers to the average optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 0 degree;OP1(0)*OP2(20) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 20 degrees;OP1(0)*OP2(30) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 30 degrees; andOP1(0)*OP2(40) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 40 degrees.

[0087] Table 3 provided below summarizes average and maximum optical transmittances of the first and second optical films 10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the different first inclusion angles al for the different wavelength regions, and average and maximum solar irradiance for the different wavelength regions.Table 3where, OP1(0)*OP2(0) refers to the average optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 0 degree;OP1(0)*OP2(20) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 20 degrees;OP1(0)*OP2(30) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 30 degrees; andOP1(0)*OP2(40) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 40 degrees.

[0088] Table 4 provided below summarizes average and maximum optical transmittances of the first and second optical fdms 10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the different first inclusion angles al for the different wavelength regions.Table 4where, OP1(0)*OP2(0) refers to the average optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 0 degree;OP1(0)*OP2(20) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 20 degrees;OP1(0)*OP2(30) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 30 degrees; andOP1(0)*OP2(40) refers to the average optical transmittance of the first and second optical films10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 incident at the first incident angle 01 of about 0 degree on the first optical film 10 and the first inclusion angle al of about 40 degrees.

[0089] FIG. 4B is a graph 450 depicting the optical transmittance OP1 *OP2 of the first and second optical films 10, 20 of the optical film assembly 200, in combination, and the solar spectrum 120 for an infrared wavelength region from about 1000 nm to about 1250 nm, according to an embodiment of the present disclosure. Specifically, FIG. 4B shows a magnified version of the graph 400 of FIG. 4 A.

[0090] The graph 450 includes the curves 402, 404, 406, and 408 as shown in FIG. 4A. It is to be noted that the curve 402 depicting the optical transmittance OP POP2 of the first and second optical films 10, 20, in combination, for the substantially collimated light 40 incident at 0 degree and the first inclusion angle al of about 0 degree is interchangeably referred to as “the optical transmittance 110”.

[0091] As is apparent from the graph 450, for the substantially collimated light 40 incident on the first optical film 10 of the optical film assembly 200 at the first incident angle ql of less than about 10 degrees with the first optical film 10 disposed between the second optical film 20 and the incident light 40, for an infrared wavelength range that extends from at most about 1000 nm to at least about 1300 nm, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance of less than about15% and a maximum optical transmittance of less than about 20% when the first inclusion angle al is greater than about 20 degrees.

[0092] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 of the optical film assembly 200 at the first incident angle ql with the first optical film 10 disposed between the second optical film 20 and the incident light 40, for the infrared wavelength range that extends from at most about 900 nm to at least about 1400 or at most about 800 nm to at least about 1500, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance of less than about 12.5%, less than about 10%, less than about 7.5% less than about 5%, less than about 4%, less than about 3%, or less than about 2% and the maximum optical transmittance of less than about 17.5%, less than about 15%, less than about 12.5%, less than about 10%, less than about 7.5%, or less than about 5% when the first inclusion angle al is greater than about 25 degrees, greater than about 30 degrees, greater than about 35 degrees, greater than about 40 degrees, greater than about 45 degrees, or greater than about 50 degrees.

[0093] As is apparent from the curve 408 in the graphs 400, 450, in some embodiments, for the substantially collimated light 40 incident on the first optical film 10 of the optical film assembly 200 at the first incident angle ql of about 0 degree with the first optical film 10 disposed between the second optical film 20 and the incident light 40, for the infrared wavelength range that extends from at most about 800 nm to at least about 1500 nm, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance of about 3.4% and the maximum optical transmittance of less than about 8.3% when the first inclusion angle al is about 40 degrees.

[0094] Further, when the first inclusion angle al is reduced to less than about 10 degrees, then a plot of the optical transmittance 110 of the first and second optical films 10, 20 of the optical film assembly 200, in combination, as a function of wavelength includes a global peak Pl of greater than about 20% in the infrared wavelength range with a corresponding full width at half maximum (FWHM) Ql of greater than about 10 nm.

[0095] In some embodiments, when the first inclusion angle al is reduced to less than about 9 degrees, about 8 degrees, about 7 degrees, about 6 degrees, about 5 degrees, about 4 degrees, about 3 degrees, about 2 degrees, or about 1 degree, then the plot of the optical transmittance 110 of the first and second optical films 10, 20 of the optical film assembly 200, in combination, as the function of wavelength includes the global peak Pl of greater than about 25%, greater than about 30%, greater than about 35%, greater than about 40%, or greater than about 45% in the infrared wavelength range with the corresponding FWHM Ql of greater than about 15 nm, greater than about 20 nm, greater than about 25 nm, greater than about 30 nm, greater than about 35 nm, greater than about 40 nm, greater than about 45 nm, or greater than about 50 nm.

[0096] As is apparent from the graph 450, in some embodiments, when the first inclusion angle al is reduced to about 0 degree, then the plot of the optical transmittance 110 of the first and second optical films 10, 20 of the optical film assembly 200, in combination, as the function of wavelength includes the global peak Pl in the infrared wavelength range (e.g., a wavelength range W6 extending from 1075 nm to about 1175 nm) with the corresponding FWHM QI of about 50 nm and a transmittance T1 of about 42%.

[0097] Referring again FIGS. 1 to 4B, as is apparent, for the substantially collimated light 40 incident on the first optical film 10 of the optical film assembly 200 at the first incident angle 01 of less than about 10 degrees with the first optical film 10 disposed between the second optical film 20 and the incident light 40, and for the at least one polarization state, the optical transmittance 110 of the first and second optical films 10, 20 of the optical film assembly 200, in combination, versus wavelength in a wavelength range of interest extending from about 400 nm to about 1700 nm, includes a plurality of alternating high transmittance continuous wavelength regions and high reflectance continuous wavelength regions.

[0098] The high transmittance continuous wavelength regions lie in the blue and red wavelength ranges Wl, W3 and may be interchangeably referred to as “the high transmittance continuous wavelength regions Wl, W3”.

[0099] The high reflectance continuous wavelength regions lie in the green wavelength range W2 and an infrared wavelength range W8 extending from about 750 nm to about 1700 nm and may be interchangeably referred to as “the high reflectance continuous wavelength regions W2, W8”. Specifically, a first one of the high reflectance continuous wavelength regions lies in the green wavelength F2 disposed in the green wavelength range W2 extending from about 510 nm to about 600 nm, and a second one of the high reflectance continuous wavelength regions lies in an infrared wavelength F7 disposed in the infrared wavelength range W8 extending from about 750 nm to about 1700 nm.

[0100] The high transmittance continuous wavelength regions and the high reflectance continuous wavelength regions may be collectively referred to as the continuous wavelength regions Wl, W2, W3, W8.

[0101] Each of the continuous wavelength regions Wl, W2, W3, W8 is at least 20 nm wide. In some embodiments, each of the continuous wavelength regions Wl, W2, W3, W8 is at least 25 nm, at least 30 nm, at least 35 nm, at least 40 nm, at least 50 nm, at least 60 nm, at least 70 nm, at least 100 nm, at least 500 nm, or at least 1000 nm wide.

[0102] Each of the high transmittance continuous wavelength regions Wl, W3 has an average optical transmittance of at least 40%, and each of the high reflectance continuous wavelength regions W2, W8 has the average optical reflectance of at least 40%. In some embodiments, each of the high transmittance continuous wavelength regions Wl, W3 has the average optical transmittance of at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, atleast 85%, at least 90%, or at least 95%, and each of the high reflectance continuous wavelength regions W2, W8 has the average optical reflectance of at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, or at least 95%.

[0103] Further, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the optical transmittance of less than about 20% at the infrared wavelength F7 and when the first inclusion angle al is reduced to less than about 10 degrees, the optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, increases at the infrared wavelength F7 by at least 5%.

[0104] In some embodiments, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the optical transmittance of less than about 17.5%, less than about 15%, less than about 12.5%, less than about 10%, less than about 7.5%, less than about 5%, less than about 2.5%, or less than about 1.5% at the infrared wavelength F7 and when the first inclusion angle al is reduced to less than about 9 degrees, less than about 8 degrees, less than about 7 degrees, less than about 6 degrees, less than about 5 degrees, less than about 4 degrees, less than about 3 degrees, less than about 2 degrees, or less than about 1 degree, the optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, increases at the infrared wavelength F7 by at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, or at least 50%.

[0105] Further, referring to FIGS. 1 to 4B, as is apparent, for the substantially collimated light 40 incident on the first optical film 10 of the optical film assembly 200 at the first incident angle 01 of less than about 10 degrees with the first optical film 10 disposed between the second optical film 20 and the incident light 40, the optical transmittance 110 of the first and second optical films 10, 20 of the optical film assembly 200, in combination, versus wavelength includes the high reflectance continuous green wavelength region W2 disposed between the high transmittance continuous blue and red wavelength regions Wl, W3 in a continuous visible wavelength range W0 extending from about 420 nm to about 680 nm.

[0106] In some embodiments, the first inclusion angle al is sufficiently large so that the maximum optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, in the continuous first infrared wavelength range W8 extending from about 750 nm to about 1500 nm is less than about 20%. In some embodiments, the first inclusion angle al is greater than or equal to about 30 degrees so that the maximum optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, in the continuous first infrared wavelength range W8 is less than about 17.5%, less than about 15%, less than about 12.5%, less than about 10%, less than about 7.5%, or less than about 5%.

[0107] In some embodiments, the incident light 40 includes the solar spectrum 120 having an average irradiance II in the visible wavelength range W0 and an average irradiance 12 in a continuous second infrared wavelength range W7 extending from about 1040 nm to about 1200 nm. In someembodiments, the continuous second infrared wavelength range W7 may be interchangeably referred to as “the intermediary infrared wavelength range W7”. Further, the infrared wavelength F7 may be interchangeably referred to as “the first intermediary infrared wavelength F7”.

[0108] A ratio of the average irradiance II and the average irradiance 12 is greater than or equal to about 2. In other words, 11 / 12 > 2. In some embodiments, 11 / 12 > 2.5, 11 / 12 > 3, 11 / 12 > 3.5, 11 / 12 > 4, 11 / 12 > 4.5, or 11 / 12 > 5.

[0109] In some embodiments, the incident light 40 includes the solar spectrum 120 having the average irradiance II of about 1.3 in the visible wavelength range W0 and the average irradiance 12 of about 0.3 in the continuous second infrared wavelength range W7. Further, in some embodiments, the ratio of the average irradiance II and the average irradiance 12 is about 4.3.

[0110] Further, when the first inclusion angle al is reduced to less than about 10 degrees, the optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, increases to greater than about 20% in the continuous second infrared wavelength range W7.

[0111] In some embodiments, when the first inclusion angle al is reduced to less than about 9 degrees, less than about 8 degrees, less than about 7 degrees, less than about 6 degrees, less than about 5 degrees, less than about 4 degrees, less than about 3 degrees, less than about 2 degrees, or less than about 1 degree, the optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, increases to greater than about 25%, greater than about 30%, greater than about 35%, greater than about 40%, greater than about 45%, or greater than about 50% in the continuous second infrared wavelength range W7.

[0112] FIG. 5 shows a graph 500 depicting the optical transmittance OP1*OP2 of the first and second optical films 10, 20 of the optical film assembly 200, in combination, for the substantially collimated light 40 (shown in FIG. 1) incident on the first optical film 10 and the different first inclusion angles al, and the solar spectrum 120, according to an embodiment of the present disclosure. The graph 500 includes only the curves 402, 408, and 120 as shown in FIG. 4A for clarity purposes.

[0113] Referring to FIGS. 1 to 5, as is apparent, for the substantially collimated incident light 46, for the first incident angle (31 of less than about 10 degrees for each of the first and second optical films 10, 20, and for the at least one polarization state, a ratio OP2 / OP1 of the optical transmittance OP2 of the second optical film 20 to the optical transmittance OP1 of the first optical film 10 is greater than about 1.5 for at least the first green wavelength F2 within the green wavelength range W2 extending from about 500 nm to about 560 nm.

[0114] In some embodiments, for the substantially collimated incident light 46, for the first incident angle (31 for each of the first and second optical films 10, 20, and for the at least one polarization, the ratio OP2 / OP1 of the optical transmittance of the second optical film 20 to the optical transmittance of the first optical film 10 is greater than about 2, greater than about 5, greater thanabout 10, greater than about 15, greater than about 20, greater than about 25, greater than about 30, greater than about 35, greater than about 40, or greater than about 50 for at least the first green wavelength F2 within the green wavelength range W2.

[0115] In some embodiments, for the substantially collimated incident light 46, for the first incident angle (31 of about 0 degree for each of the first and second optical films 10, 20, and for the at least one polarization state, the ratio OP2 / OP1 of the optical transmittance OP2 of about 81.4% of the second optical film 20 to the optical transmittance OP1 of about 2.2% of the first optical film 10 is about 36.2% for at least the first green wavelength F2 within the green wavelength range W2.

[0116] Table 5 provided below summarizes the ratios OP2 / OP1 of the optical transmittance s OP2, OP1 of the second optical film 20 to the first optical film 10 for the substantially collimated incident light 46 incident at the different incident angles.Table 5where, OP2(0) / OP1(0) refers to the ratio OP2 / OP1 of the optical transmittances OP2, OP1 of the second optical film 20 to the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 0 degree on the first and second optical films 10, 20;OP2(10) / OP1(10) refers to the ratio OP2 / OP1 of the optical transmittances OP2, OP1 of the second optical film 20 to the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 10 degrees on the first and second optical films 10, 20;OP2(20) / OP1(20) refers to the ratio OP2 / OP1 of the optical transmittances OP2, OP1 of the second optical film 20 to the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 20 degrees on the first and second optical films 10, 20;OP2(30) / OP1(30) refers to the ratio OP2 / OP1 of the optical transmittances OP2, OP1 of the second optical film 20 to the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 30 degrees on the first and second optical films 10, 20; andOP2(40) / OP1(40) refers to the ratio OP2 / OP1 of the optical transmittances OP2, OP1 of the second optical film 20 to the first optical film 10 for the substantially collimated incident light 46 incident at the incident angle of about 40 degrees on the first and second optical films 10, 20.

[0117] Further, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W4 extending from about 740 nm to about 1040 nm, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance of less than about 20%, where reducing the first inclusion angle al to less than about 10 degrees, increases the optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, by at least 10% for at least the first intermediary infrared wavelength F7 in the intermediary infrared wavelength range W7 extending from about 1040 nm to about 1700 nm.

[0118] In some embodiments, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W4, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance of less than about 17.5%, less than about 15%, less than about 12.5%, less than about 10%, or less than about 7.5%, where reducing the first inclusion angle al to less than about 8 degrees, less than about 6 degrees, less than about 4 degrees, less than about 2 degrees, or less than about 1 degree, increases the optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, by at least 10% for the at least the first intermediary infrared wavelength F7 in the intermediary infrared wavelength range W7.

[0119] Further, for the substantially collimated light 40 incident on the first optical film 10 at the first incident angle 01 with the first optical film 10 disposed between the second optical film 20 and the light source 30, for the first infrared wavelength range W4, and for the at least one polarization state, the first and second optical films 10, 20 of the optical film assembly 200, in combination, have the average optical transmittance of about 6.3% for the first inclusion angle al of about 40 degrees and of about 6.6% for the first inclusion angle al of about 30 degrees, where reducing the first inclusion angle al to about 0 degree, increases the optical transmittance of the first and second optical films 10, 20 of the optical film assembly 200, in combination, by at least 35% for at the least the first intermediary infrared wavelength F7 in the intermediary infrared wavelength range W7.

[0120] Referring to FIGS. 1-5, therefore, the optical film assembly 200 is configured to receive the emitted light 40 from the light source 30 and transmit at least 50% of the received emitted light 40 for each of the first and third wavelengths Fl, F3 and reflect at least 50% of the received emitted light 40 for each of the second, fourth, and fifth wavelengths F2, F4, F5.

[0121] Specifically, the optical film assembly 200 is configured to receive the emitted light 40 from the light source 30 and transmit at least 50% of the received emitted light 40 for each of the first and third wavelengths Fl, F3 as transmitted light 41, 43 and reflect at least 50% of the receivedemited light 40 for each of the second, fourth, and fifth wavelengths F2, F4, F5 as reflected light 42, 44, 45.

[0122] More specifically, the optical film assembly 200 is configured to receive the emitted light 40 from the light source 30 and transmit at least 50% of the received emitted light 40 for the first wavelength Fl as the transmited light 41 and transmit at least 50% of the received emitted light 40 for the third wavelength F3 as the transmited light 43. Furthermore, the optical film assembly 200 is configured to receive the emitted light 40 from the light source 30 and reflect at least 50% of the received emitted light 40 for the second wavelength F2 as the reflected light 42, reflect at least 50% of the received emitted light 40 for the fourth wavelength F4 as the reflected light 44, and reflect at least 50% of the received emited light 40 for the fifth wavelength F5 as the reflected light 45.

[0123] In some embodiments, the optical film assembly 200 is configured to receive the emited light 40 from the light source 30 and transmit at least 60%, at least 70%, at least 80%, or at least 90% of the received emitted light 40 for each of the first and third wavelengths Fl, F3 and reflect at least 60%, at least 70%, at least 80%, or at least 90% of the received emited light 40 for each of the second, fourth, and fifth wavelengths F2, F4, F5.

[0124] Further, the first light receiving area 50 receives the transmited light 41, 43 having the first and third wavelengths Fl, F3, the second light receiving area 51 receives the reflected light 42, 44 having the second and fourth, but not the fifth, wavelengths F2, F4, and the third light receiving area 52 receives the reflected light 45 having the fifth, but not the second or the fourth, wavelengths F5.

[0125] In some embodiments, the optical system 300 is configured to receive the emited light 40 from the light source 30 and transmit at least 50% of the received emitted light 40 for each of the first and third wavelengths Fl, F3 and reflect at least 50% of the received emitted light 40 for each of the second, fourth, and fifth wavelengths F2, F4, F5 for each of the mutually orthogonal first and second polarization states.

[0126] In some embodiments, the optical film assembly 200 is configured to receive the emited light 40 from the light source 30 and transmit at least 60%, at least 70%, at least 80%, or at least 90% of the received emitted light 40 for each of the first and third wavelengths Fl, F3 and reflect at least 60%, at least 70%, at least 80%, or at least 90% of the received emited light 40 for each of the second, fourth, and fifth wavelengths F2, F4, F5 for each of the mutually orthogonal first and second polarization states.

[0127] Thus, the optical system 300 including the optical film assembly 200 may be configured to substantially transmit emitted light 40 having the first and third wavelengths Fl, F3 and substantially reflect the emitted light 40 having the second, fourth, and fifth wavelengths F2, F4, F5. Specifically, the emited light 40 having the first and third wavelengths Fl, F3 is substantially transmitted through the optical film assembly 200 to the first light receiving area 50, and the emittedlight 40 having the second, fourth, and fifth wavelengths F2, F4, F5 is substantially reflected from the optical film assembly 200 to the second and third light receiving areas 51, 52.

[0128] Hence, the first through fifth wavelengths F1-F5 of the emitted light 40 may be received in either the first light receiving area 50, the second light receiving area 51, or the third light receiving area 52 depending upon where they can be effectively utilized. For instance, the emitted light 40 having the first and third wavelengths Fl, F3 may be used for food production in a greenhouse setup, and the emitted light 40 having the second, fourth, and fifth wavelengths F2, F4, F5 may be used for generating electricity. In addition, the generated electricity may be utilized in operations of the greenhouse setup. Hence, the optical system 300 may reduce costs of the greenhouse setup and may also generate less carbon footprints. The second, fourth, and fifth wavelengths F2, F4, F5 may optionally be used as a heat source.

[0129] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0130] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

Claims

CLAIMS1. An optical system comprising: an optical film assembly comprising a plurality of polymeric layers numbering at least 10 in total, each of the polymeric layers having an average thickness of less than about 500 nm; a light source disposed on a first major side of the optical film assembly and configured to emit light having at least first through fifth sequentially increasing wavelengths, each of the wavelengths in the sequence of the at least five wavelengths greater than the smaller wavelengths in the sequence by at least 10 nm, the first through the third wavelengths being visible wavelengths in a visible wavelength range extending from about 420 nm to about 680 nm, the second wavelength being a green wavelength within a green wavelength range extending from about 500 nm to about 560 nm, the fourth and fifth wavelengths being infrared wavelengths in an infrared wavelength range extending from about 700 nm to about 2500 nm; a first light receiving area disposed on a second, opposite the first, major side of the optical film assembly; and spaced apart second and third light receiving areas disposed on the first major side of the optical film assembly; such that the optical film assembly is configured to receive the emitted light from the light source and transmit at least 50% of the received emitted light for each of the first and third wavelengths and reflect at least 50% of the received emitted light for each of the second, fourth, and fifth wavelengths, the first light receiving area receiving the transmitted light having the first and third wavelengths, the second light receiving area receiving the reflected light having the second and fourth, but not the fifth, wavelengths, and the third light receiving area receiving the reflected light having the fifth, but not the second or the fourth wavelengths.

2. The optical system of claim 1, wherein the optical film assembly comprises first and second optical films forming a first inclusion angle of between about 15 degrees and about 80 degrees therebetween, each of the first and second optical films comprising a plurality of polymeric layers numbering at least 10 in total, each of the polymeric layers having an average thickness of less than about 500 nm.

3. The optical system of claim 2, wherein for a substantially collimated incident light, for a first incident angle of less than about 10 degrees for each of the first and second optical films, for at least one polarization state, and continuous blue, green, and red wavelength ranges extending continuously respectively from about 400 nm to about 480 nm, from about 510 nm to about 600 nm, and from about 640 nm to about 680 nm, each of the first and second optical films has an average optical transmittance of greater than about 50% in each of the blue and red wavelength ranges, the first optical film has anaverage optical transmittance of less than about 20% in the green wavelength range, and the second optical film has an average optical transmittance of greater than about 50% in the green wavelength range.

4. The optical system of claim 2, wherein for a substantially collimated incident light, for a second incident angle of greater than about 25 degrees for each of the first and second optical films, for at least one polarization state, and continuous blue, green, and red wavelength ranges extending continuously respectively from about 400 nm to about 480 nm, from about 510 nm to about 600 nm, and from about 640 nm to about 680 nm, the first optical film has average optical transmittances of less than about 70%, less than about 50%, and less than about 20% in the respective blue, green, and red wavelength ranges, and the second optical film has an average optical transmittance of greater than about 50% in each of the blue, green, and red wavelength ranges.

5. The optical system of claim 2, wherein for a substantially collimated incident light, for each of a first incident angle of less than about 10 degrees for each of the first and second optical films, and a second incident angle of greater than about 25 degrees for each of the first and second optical films, for at least one polarization state, and continuous first and second infrared wavelength ranges extending continuously respectively from about 740 nm to about 1040 nm and from about 1200 nm to about 1700 nm, the first optical film has an average optical transmittance of less than about 25% in the first infrared wavelength range and an average optical transmittance of greater than about 60% in the second infrared wavelength range, and the second optical film has an average optical transmittance of greater than about 60% in the first infrared wavelength range and an average optical transmittance of less than about 25% in the second infrared wavelength range.

6. The optical system of claim 2, wherein for a substantially collimated light incident on the first optical film at a first incident angle of less than about 10 degrees with the first optical film disposed between the second optical film and the light source, for a first infrared wavelength range extending from about 740 nm to about 1040 nm, and for the at least one polarization state, the first and second optical films of the optical film assembly, in combination, have an average optical transmittance that remains less than about 20% as the first inclusion angle is reduced to about zero.

7. The optical system of claim 2, wherein for a substantially collimated light incident on the first optical film at a first incident angle of less than about 10 degrees with the first optical film disposed between the second optical film and the light source, for a first infrared wavelength range extending from about 1200 nm to about 1700 nm, and for the at least one polarization state, the first and second optical films of the optical film assembly, in combination, have an average optical transmittance that remains less than about 20% as the first inclusion angle is reduced to about zero.

8. The optical system of claim 2, wherein for a substantially collimated light incident on the first optical film at a first incident angle of less than about 10 degrees with the first optical film disposed between the second optical film and the light source, for a green wavelength range extending from about 510 nm to about 600 nm, for a red wavelength range extending from about 640 nm to about 680 nm, and for the at least one polarization state, and as the first inclusion angle is reduced to about zero, the first and second optical films of the optical film assembly, in combination, have an average optical transmittance that remains less than about 20% in the green wavelength range and remains greater than about 50% in the red wavelength range.

9. The optical system of claim 2, wherein for a substantially collimated light incident on the first optical film at a first incident angle of less than about 10 degrees with the first optical film disposed between the second optical film and the light source, for the at least one polarization state, and as the first inclusion angle is reduced to about zero, the first and second optical films of the optical film assembly, in combination, have an average optical transmittance that remains greater than about 40% in a blue wavelength range extending from about 400 nm to about 480 nm.

10. The optical system of claim 1, wherein the light source has an intensity spectrum substantially similar to a solar spectrum at least in a continuous wavelength range extending from about 400 nm to about 2500 nm.

11. The optical system of claim 1, wherein the first light receiving area comprises one or more plants.

12. The optical system of claim 1, wherein at least one of the second and third light receiving areas comprises one or more optical detectors configured to convert at least a portion of an incident light to electricity or heat.

13. The optical system of claim 1 configured to receive the emitted light from the light source and transmit at least 50% of the received emitted light for each of the first and third wavelengths and reflect at least 50% of the received emitted light for each of the second, fourth, and fifth wavelengths, for each of mutually orthogonal first and second polarization states.

14. An optical film assembly comprising first and second optical films forming a first inclusion angle of between about 15 degrees and about 80 degrees therebetween, each of the first and second optical films comprising a plurality of polymeric layers numbering at least 10 in total, each of the polymeric layers having an average thickness of less than about 500 nm;such that, for a substantially collimated incident light, for a first incident angle of less than about 10 degrees for each of the first and second optical films, and for at least one polarization state, a ratio of an optical transmittance of the second optical film to an optical transmittance of the first optical film is greater than about 1.5 for at least a first green wavelength within a green wavelength range extending from about 500 nm to about 560 nm; and for a substantially collimated light incident on the first optical film at the first incident angle with the first optical film disposed between the second optical film and the incident light, for a first infrared wavelength range extending from about 740 nm to about 1040 nm, and for the at least one polarization state, the first and second optical films of the optical film assembly, in combination, have an average optical transmittance of less than about 20%, and wherein, reducing the first inclusion angle to less than about 10 degrees, increases an optical transmittance of the first and second optical films of the optical film assembly, in combination, by at least 10% for at least a first intermediary infrared wavelength in an intermediary infrared wavelength range extending from about 1040 nm to about 1700 nm.

15. An optical film assembly comprising first and second optical films forming a first inclusion angle of greater than about 5 degrees therebetween, each of the first and second optical films comprising a plurality of polymeric layers numbering at least 10 in total, each of the polymeric layers having an average thickness of less than about 500 nm; such that for a substantially collimated light incident on the first optical film of the optical film assembly at a first incident angle of less than about 10 degrees with the first optical film disposed between the second optical film and the incident light, for an infrared wavelength range that extends from at most about 1000 nm to at least about 1300 nm, and for at least one polarization state, the first and second optical films of the optical film assembly, in combination, have an average optical transmittance of less than about 15% and a maximum optical transmittance of less than about 20% when the first inclusion angle is greater than about 20 degrees; wherein, when the first inclusion angle is reduced to less than about 10 degrees, then a plot of an optical transmittance of the first and second optical films of the optical film assembly, in combination, as a function of wavelength comprises a global peak of greater than about 20% in the infrared wavelength range with a corresponding full width at half maximum (FWHM) of greater than about 10 nanometers.

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