KR101999981B1 - Transparent back sheet for light module, method for manufacturing the same and light module comprising the same - Google Patents

Abstract

The present invention relates to a transparent back sheet for an optical module, a manufacturing method thereof, and an optical module. This application claims the benefit of U.S. Patents And a surface layer formed on the substrate; And a transparent back sheet for an optical module including a transparent pigment which absorbs ultraviolet rays and reflects infrared rays, a method for producing the transparent back sheet, and an optical module including the transparent back sheet. According to the present application, the temperature rise of the installation structure can be prevented and the weather resistance can be improved.

Description

TECHNICAL FIELD [0001] The present invention relates to a transparent back sheet for an optical module, a method of manufacturing the same and an optical module,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent back sheet for an optical module, a method of manufacturing the same and an optical module, and more particularly to a transparent back sheet for an optical module, which is capable of selectively reflecting light while maintaining transparency, Sheet, a method of manufacturing the same, and an optical module.

In recent years, interest in renewable energy and clean energy has increased due to global environmental problems and depletion of fossil fuels. Among them, energy using light is attracting attention as a representative pollution-free energy source that can solve environmental pollution problem and fossil fuel depletion problem. For example, photovoltaic cells such as solar cells are rapidly spreading into residential and industrial applications.

Photovoltaic cells are devices that convert sunlight to electrical energy, which typically require long exposure to the external environment to easily absorb sunlight, so that various packaging to protect the internal components is performed, And these units are generally referred to as optical modules.

Also, most optical modules, for example, optical modules such as a solar cell module, include a back sheet for protecting internal elements (e.g., solar cell). 1 shows a conventional optical module, which is a sectional view showing a solar cell module in detail. 1 shows a back sheet according to the prior art.

1, a solar cell module generally includes a transparent tempered glass 3, a front encapsulant layer 2a, a plurality of solar cells C, a back encapsulant layer 2b, And the sheet 1 are sequentially stacked. The plurality of solar cells C are electrically connected to each other and are sealed by the front and rear sealing material layers 2a and 2b. That is, as shown in FIG. 1, the solar cell C is packed and fixed between the front sealing material layer 2a and the rear sealing material layer 2b.

The solar cell module is required to have a long life without a reduction in output over a long period of time. For such longevity, the back sheet 1 should be able to block moisture and oxygen which adversely affect the solar cell C, and to prevent deterioration due to ultraviolet rays or the like. Accordingly, the backsheet 1 should be made of a material having heat resistance, durability, and the like that can withstand high temperature, humidity, ultraviolet rays, etc. in order to prolong the module life.

Generally, the backsheet 1 comprises a base material 1a and a surface layer 1b formed on both sides of the base material 1a. As the substrate 1a, a heat-resistant polyethylene terephthalate (PET) film is mainly used. As the surface layer 1b, a fluorinated polymer film such as polyvinylidene fluoride (PVDF) is mainly used. The fluorine-based polymer has an excellent durability. For example, Korean Patent No. 10-1022820 and Korean Patent Laid-open No. 10-2011-0020227 disclose techniques related to this.

Further, most of the back sheet 1 has transparency. That is, the substrate 1a and the surface layer 1b are made to have transparency. Such a transparent back sheet 1 is mainly used for a Bi-Facial light receiving system installed in a window or a greenhouse of a building, a BIPV (Building Integrated Photovoltaic System), and the like.

However, the transparent back sheet 1 according to the related art has a problem of raising the internal temperature of the installed structure. That is, the transparent back sheet 1 according to the related art has a problem of raising the temperature inside the building due to transmission of infrared rays (IR).

In addition, most of the transparent back sheet 1 according to the related art has a problem in that weather resistance is deteriorated due to transmission of ultraviolet rays (UV). That is, due to the transmission of ultraviolet rays (UV), yellowing occurs in the PET film constituting the base material 1a and the weather resistance is deteriorated. In order to prevent this, in some cases, an ultraviolet absorber is added to the surface layer 1b. However, in this case, there is a problem in that the cost and process of the ultraviolet absorber are increased.

Korean Patent No. 10-1022820 Korea Patent Publication No. 10-2011-0020227

Accordingly, the present application is directed to providing a transparent back sheet for an optical module, a method of manufacturing the same, and an optical module.

The present application aims to provide a transparent back sheet for an optical module, an optical module and a method for manufacturing the same, which selectively reflects light while maintaining transparency, thereby preventing an increase in the temperature of the mounting structure and improving weather resistance .

[0002]

materials;

A surface layer formed on the substrate; And

There is provided a transparent back sheet for an optical module comprising a transparent pigment which absorbs ultraviolet rays and reflects infrared rays.

According to the present application, a transparent back sheet for an improved optical module, a method of manufacturing the same, and an optical module can be provided. More specifically, the present application has an effect of selectively absorbing / reflecting / transmitting light while maintaining transparency, thereby preventing temperature rise of the installation structure and improving weather resistance.

1 is a cross-sectional view of an optical module and a back sheet according to the related art.
2 is a cross-sectional structural view of a transparent back sheet for an optical module according to an exemplary embodiment of the present application.
3 is a conceptual diagram of a transparent back sheet for an optical module according to an exemplary embodiment of the present application.
4 is a cross-sectional structural view of an optical module according to an exemplary embodiment of the present application.
5 is a graph showing a light transmittance according to a wavelength of a transparent back sheet for an optical module according to an embodiment of the present application.

Embodiments of the present application will now be described with reference to the accompanying drawings. In the description of the present application, a detailed description of commonly known general functions or configurations will be omitted. The accompanying drawings schematically illustrate the present invention in order to facilitate understanding of the present application, and thus the scope of the present application is not limited thereto. In addition, in the accompanying drawings, portions not related to the description are omitted for clarification of the present application. In the accompanying drawings, the thickness is enlarged in order to clearly illustrate various layers and regions, and the scope of the present application is not limited by the thickness, size and ratio shown in the drawings.

FIG. 2 shows a transparent back sheet (hereinafter abbreviated as "transparent back sheet") for an optical module according to an exemplary embodiment of the present application.

Referring to FIG. 2, a transparent back sheet 100 according to the present application includes a substrate 10, a surface layer 20 (30) formed on the substrate 10; And transparent pigments. And they are all transparent. In the present application, transparency may mean that the illuminated light (visible light) has a transmittance of, for example, greater than 50%, such as greater than 60% or greater than 80%, for example, on a vertical line.

The number of the surface layers 20 and 30 may be one or two. That is, the surface layers 20 and 30 may be formed on one side or both sides of the substrate 10. Fig. 2 illustrates an example of the surface layer 20 (30) formed on both surfaces of the substrate 10 as an exemplary embodiment of the present application. Specifically, the transparent back sheet 100 according to the present application comprises, in accordance with one exemplary embodiment, a substrate 10; A first surface layer 20 formed on one side (top surface in the figure) of the substrate 10; And a second surface layer 30 formed on the other side (lower surface in the figure) of the substrate 10. [

In the present application, the laminated structure of the transparent back sheet 100 is not limited. The transparent back sheet 100 according to the present application may include one or more functional transparent layers including one or more surface layers 20 and 30 in addition to the substrate 10.

Further, in the present application, the substrate 10 and the surface layers 20 and 30 may be in direct contact with each other, or intervening layers may be interposed therebetween. For example, a primer layer (not shown) may be formed between the substrate 10 and the surface layers 20 and 30. At this time, the primer layer is for the interlayer adhesive force between the substrate 10 and the surface layers 20 and 30, and may include resin adhesives such as acrylic, urethane, epoxy, and polyolefin adhesives.

The transparent paint is selected from a transparent material that absorbs ultraviolet (UV) light and reflects infrared (IR) light. The transparent pigment ensures transparency and transmits visible light. That is, in the present application, the transparent paint selectively absorbs / reflects / transmits light, which is selected to absorb ultraviolet (UV), reflect infrared (IR), and transmit visible light.

Hereinafter, exemplary components of the transparent back sheet 100 according to the present application will be described.

The substrate 10 is not particularly limited as long as it is transparent. Various materials known in the art can be used for the base material 10, and it can be suitably selected and used according to required functions and applications. The substrate 10 can be selected from a polymer film or the like in one example. Specific examples of the substrate 10 include a single sheet such as a polyester film, an acrylic film, a polyolefin film, a polyamide film, and a polyurethane film, a laminated sheet, or a pneumatic article.

The base material 10 may comprise a polyester resin composed of a polymer film and favorable in terms of heat resistance and the like as a base resin, according to an exemplary embodiment. Examples of the polyester resin include at least one selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and polybutylene terephthalate (PBT) But is not limited thereto. The substrate 10 may be selected as a polyolefin-based film, according to another exemplary embodiment. At this time, the polyolefin film is, for example, a polypropylene (PP) film.

Further, the base material 10 may be subjected to an adhesion strengthening treatment for improving adhesion with the surface layers 20 and 30 described later. For example, high-frequency spark discharge treatment such as corona treatment or plasma treatment is applied to one side or both sides of the substrate 10; Heat treatment; Flame treatment; Anchor treatment; Coupling agent treatment; Surface treatment such as primer treatment or chemical activation treatment using gaseous Lewis acid (ex. BF3), sulfuric acid or high temperature sodium hydroxide can be performed. The surface treatment method may be performed by any well-known means commonly used in the general industrial field. The bonding force with the surface layers 20 and 30 can be improved through the surface treatment as described above.

In addition, the substrate 10 may be provided with an inorganic vapor deposition layer on one side or both sides of the substrate 10 from the viewpoint of further improvement of moisture barrier properties and the like. The kind of the inorganic substance is not particularly limited and can be adopted without limitation as long as it has a moisture barrier property. For example, silicon oxide or aluminum oxide can be used. The method of forming the inorganic deposit layer on one surface or both surfaces of the substrate 10 is not particularly limited and may be, for example, vapor deposition. When the inorganic vapor deposition layer is formed on one side or both sides of the substrate 10 as described above, the inorganic vapor deposition layer may be formed on the surface of the substrate 10, and then the above-described surface treatment may be performed on the vapor deposition layer. That is, in one embodiment of the present application, the spark discharge treatment, the flame treatment, the coupling agent treatment, the anchorage treatment, or the chemical activation treatment described above may be performed to further improve the adhesive force on the deposition layer formed on the substrate 10 have.

The thickness of the substrate 10 is not particularly limited, and may range, for example, from about 20 탆 to 1000 탆, or from about 50 탆 to 300 탆. By adjusting the thickness of the base material 10 to the above range, it is possible to improve electrical insulation, moisture barrier properties, mechanical properties and handling properties of the back sheet 100. In the present application, the thickness of the substrate 10 is not limited to the above-mentioned range, and it can be suitably adjusted as necessary.

The surface layer 20 (30) is formed on one side or both sides of the substrate 10 as described above, and it can be selected from a coating layer and a film layer. Specifically, the surface layers 20 and 30 may be formed by bonding a film on the substrate 10, or may be formed by coating and curing the resin composition. In this case, when the surface layers 20 and 30 are films, they may be bonded to the substrate 10 through an adhesive, or may be bonded by thermal fusion (thermal lamination) or the like.

The surface layers 20 and 30 include a base resin. At this time, the base resin may be one having durability (weather resistance) or the like. The surface layers 20 and 30 are base resins favorable in terms of durability (weather resistance), and may include, for example, a fluorine resin. More specifically, the surface layer 20 (30) may be selected from a fluorine resin coating layer or a fluorine resin film layer.

In the present application, the fluorine-based resin may contain one or more fluorine (F) elements in the molecule. The fluororesin may be, for example, vinylidene fluoride (VDF), vinyl fluoride (VF), tetrafluoroethylene (TFE), hexafluoropropylene (HFP), chlorotriene Perfluoroethyl vinyl ether (PEVE), perfluoroethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE), perfluoroethyl vinyl ether perfluoro (ethylvinylether), perfluoropropyl vinyl ether (PPVE), perfluorohexyl vinyl ether (PHVE), perfluoro-2,2-dimethyl-1,3-dioxole -2-methylene-4-methyl-1,3-dioxolane (PMD), and the like, in a polymerized form, or a mixture thereof.

The fluororesin may be a homopolymer or a copolymer including, for example, vinylidene fluoride (VDF) in a polymerized form; Or vinyl fluoride (VF) in polymerized form; Or a mixture comprising two or more of the above.

The type of the comonomer that can be included in the polymer in the form of the copolymer is not particularly limited, and examples thereof include tetrafluoroethylene (TFE), hexafluoropropylene (HFP), chlorotrifluoro But are not limited to, ethylene (CTFE), trifluoroethylene, hexafluoroisobutylene, perfluorobutyl ethylene, perfluoro (methylvinylether), and perfluoroethyl vinyl ether perfluorohexyl vinyl ether (PHVE), perfluoro-2,2-dimethyl-1,3-dioxole (PDD), and perfluoro-2 Methylene-4-methyl-1,3-dioxolane (PMD), and the like, and examples thereof include at least one of hexafluoropropylene and chlorotrifluoroethylene. However, Limitations include The.

The content of the comonomer contained in the copolymer is not particularly limited and may be, for example, about 0.5 to 50 wt%, 1 to 40 wt%, and 7 wt% based on the total weight of the copolymer % To 40 wt%, 10 wt% to 30 wt%, or 10 wt% to 20 wt%. By controlling the content of the comonomer in the above range, it is possible to induce effective mutual diffusion and low-temperature drying while ensuring the durability and weather resistance of the transparent back sheet 100, and further improve the adhesive force.

The fluorine-based resin may have a melting point of, for example, 80 ° C to 175 ° C, or 120 ° C to 165 ° C. It is possible to prevent the transparent back sheet 100 from being deformed during use and to adjust the melting point to 175 DEG C or less to control the solubility in the solvent and to prevent the coating The gloss of the surface can be improved.

According to an exemplary embodiment, the fluororesin may include i) a first fluororesin having a melting point of 155 ° C or lower and a softening point of 100 ° C or higher. Such a first fluorocarbon resin has a low melting point and a softening point, so that it can be mixed with other polymers in a high temperature coating process, and the noncrystalline portion increases, so that the first fluorocarbon resin is excellent in compatibility with other polymers.

In addition to the first fluorine-based resin, the fluorine-based resin may further include a second fluorine-based resin having a melting point of 155 ° C or higher and a softening point of 100 ° C or lower. At this time, the second fluororesin may be optionally used as needed. The second fluorinated resin may have a melting point of more than 155 ° C and a softening point of not more than 100 ° C.

The first fluororesin and the second fluororesin correspond to the fluororesin described above. The first fluororesin and the second fluororeshape can be classified according to the melting point and the softening point which are inherent characteristics of the polymer according to the polymerization of the monomer forming the fluororesin. The first fluorocarbon resin having a melting point of 155 ° C or less or a softening point of 100 ° C or more may account for 20% by weight or more, preferably 50% by weight or more, based on the weight of the total fluoropolymers contained in the surface layers 20 and 30, , The action according to its use may be more advantageous.

The fluorine-based resin may have a weight average molecular weight of 50,000 to 100, and may be, for example, 100,000 to 700,000, or 300,000 to 50,000, but is not limited thereto. In the present specification, the weight average molecular weight is a conversion value of standard polystyrene measured by GPC (Gel Permeation Chromatograph). In embodiments of the present application, excellent solubility and other physical properties can be secured by controlling the weight average molecular weight of the fluorine resin within the above range.

Further, in the present application, the thicknesses of the surface layers 20 and 30 are not limited. That is, the first surface layer 20 and the second surface layer 30 may have various thicknesses. The surface layers 20 and 30 may have a thickness of, for example, 5 to 300 mu m, for example, a thickness of 10 to 200 mu m, but are not limited thereto.

On the other hand, in the present application, the transparent pigment is not limited as long as it has the light sorting characteristics as described above. Specifically, the transparent pigment is not particularly limited as long as it has a light sorting characteristic of absorbing ultraviolet rays (UV), reflecting infrared rays (IR), and transmitting visible rays. More specifically, for example, the transparent pigment can be selected to absorb ultraviolet light (UV) of about 400 nm or less, reflect infrared light (IR) of about 700 nm or more, and transmit visible light of about 400 nm to 700 nm. Such a transparent pigment may use one or more selected from, for example, inorganic substances, organic substances and inorganic-organic compounds.

The transparent pigment may be selected from inorganic pigments containing silicon (Si), aluminum (Al), titanium (Ti), zinc (Zn) and tin (Sn) elements according to an exemplary embodiment of the present application . At this time, the inorganic pigment may be a crystalline inorganic substance containing the above elements or an amorphous inorganic substance. The inorganic pigment may be composed of a mixture of two or more kinds of inorganic substances, wherein each of the two or more kinds of inorganic substances contains at least one element among the above-mentioned elements.

According to one exemplary embodiment of the present application, the transparent pigment may be an inorganic pigment comprising mica, titanium oxide (TiO2), zinc oxide (ZnO) and tin oxide (SnO2). The inorganic pigment thus prepared has excellent properties in absorption of ultraviolet rays (UV), reflection of infrared rays (IR), and transmission of visible light rays. And is stable to light. The inorganic material is not particularly limited. For example, 5 to 150 parts by weight of titanium oxide (TiO2), 0.5 to 50 parts by weight of zinc oxide (ZnO), and 0.5 to 50 parts by weight of tin oxide (SnO2 0.1 to 20 parts by weight. When the composition is prepared in such a content range, it may be more effective in the characteristics as described above. Further, the above transparent pigment can be used by purchasing a product for sale. For example can be used for products such as Iriotec ^®, For example it can be used Iriotec ^® 9870.

In the present application, the transparent pigment is included in the transparent back sheet 100 according to the present application, but the constitution thereof is not limited. The transparent pigment may be formed, for example, as a separate layer. That is, the transparent back sheet 100 according to the present application may include a transparent pigment layer as a separate layer. At this time, the transparent pigment layer is formed by coating a resin composition comprising an adhesive transparent resin and a transparent pigment on the surface layers 20 and 30 or between the substrate 10 and the surface layers 20 and 30 .

According to an exemplary embodiment of the present application, the transparent pigment may be included in the surface layer 20 (30). That is, the surface layers 20 and 30 may include a transparent pigment. More specifically, the surface layers 20 and 30 may include a base resin (such as a fluororesin) and a transparent pigment. Although not particularly limited, the surface layers 20 and 30 may include 0.1 to 30 parts by weight or 0.1 to 10 parts by weight of a transparent pigment based on 100 parts by weight of the fluororesin. At this time, when the content of the transparent pigment is less than 0.1 part by weight, the light selection property depending on the content thereof may be insignificant. When the amount is more than 30 parts by weight, the content of the base resin (fluorine resin or the like) becomes relatively low, and the adhesion and durability may be lowered. In consideration of this point, the surface layers 20 and 30 may include, for example, 0.5 to 10 parts by weight or 1 to 10 parts by weight of a transparent pigment with respect to 100 parts by weight of the fluororesin.

The surface layers 20 and 30 may include a first surface layer 20 and a second surface layer 30 formed on both sides of the substrate 10 as illustrated in FIG. The transparent pigment may be contained in one or both of the first surface layer 20 and the second surface layer 30. For example, when the transparent back sheet 100 is installed, it is preferable that the surface facing the light, that is, the first surface layer 20 includes a transparent pigment.

According to another exemplary embodiment of the present application, the transparent pigment may be included in the primer layer as described above. That is, the transparent back sheet 100 according to the present application further includes a primer layer formed between the substrate 10 and the surface layers 20 and 30, wherein the primer layer may include a transparent pigment. More specifically, the primer layer may be formed by coating an adhesive composition comprising a resin adhesive and a transparent pigment for improving interlayer adhesion. Although not particularly limited, the primer layer may contain 0.1 to 30 parts by weight or 0.1 to 10 parts by weight of a transparent pigment relative to 100 parts by weight of the resin adhesive. At this time, as described above, when the content of the transparent pigment is less than 0.1 part by weight, the light-selecting property depending on the content thereof may be insignificant, and when it exceeds 30 parts by weight, the content of the resin adhesive may be relatively low and the adhesive strength may be lowered.

Further, the substrate 10 and / or the surface layers 20 and 30 may further include other additives. Specifically, at least one selected from the substrate 10 and the surface layers 20 and 30 may further include at least one additive selected from, for example, a heat stabilizer, an antioxidant, and an inorganic filler, May be those known in the art.

In addition, the transparent back sheet 100 according to the present application may further include various functional layers as necessary. Examples of the functional layer include an adhesive layer or an insulating layer.

For example, as shown in FIG. 2, the transparent back sheet 100 according to the present application includes a substrate 10 and surface layers 20 and 30 formed on both sides thereof, For example, an adhesive layer may be formed on the upper surface of the first surface layer 20. In addition, an insulating layer may be formed between the substrate 10 and the surface layer 20 (30) or between the surface of the surface layer 20 (30) or between the adhesive layer and the surface layer 20. At this time, the components constituting the adhesive layer and the insulating layer are not particularly limited, and they may be layers composed of ethylene vinyl acetate (EVA) and / or low density linear polyethylene (LDPE), for example.

Further, according to an exemplary embodiment of the present application, a primer layer may be formed between the substrate 10 and the surface layers 20 and 30 as described above. At this time, the primer layer may include resin adhesives such as acrylic, urethane, epoxy and polyolefin adhesives for the interlaminar adhesive strength. In some cases, the primer layer may include a transparent pigment having light sorting characteristics as described above.

In addition, the primer layer may comprise an oxazoline group-containing compound according to another exemplary embodiment. The primer layer may specifically include a compound containing a oxazoline group (a polymer) as a base resin, or a fluoropolymer and an oxazoline group-containing polymer as a base resin. In this case, the interlayer adhesive force with the surface layers 20 and 30 can be effectively improved. That is, at least the primer layer containing an oxazoline group-containing polymer can improve adhesion to the base material 10 through the oxazoline group and also improve adhesion to the surface layer 20 (30) containing the fluororesin through diffusion of the fluororesin It is possible to improve bonding strength and to strongly bond the substrate 10 and the surface layers 20 and 30 including the fluorine resin.

The kind of the oxazoline group-containing polymer contained in the primer layer is not particularly limited and is not limited as long as it is excellent in compatibility with the fluorine resin. In the present application, the oxazoline group-containing polymer is a homopolymer of an oxazoline group-containing monomer; Copolymers comprising an oxazoline group-containing monomer and at least one comonomer; Or mixtures thereof. ≪ / RTI >

The oxazoline group-containing polymer contained in the primer layer may form an interpenetrating polymer network (IPN) with a fluororesin. In one embodiment, the C-F2-bonded dipole of the fluorine-based resin contained in the primer layer or the surface layers 20 and 30 may have an oxazoline group or another functional group such as an ester group of the oxazoline group- It is possible to induce the interaction by van der Waals bonding, thereby further improving the interfacial adhesion at the contact interface.

The content of the oxazoline group-containing polymer contained in the primer layer is 5 parts by weight to 100 parts by weight, 10 parts by weight to 95 parts by weight, 20 parts by weight (based on the base resin of the primer layer, for example, To 80 parts by weight, 40 parts by weight to 100 parts by weight, 50 parts by weight to 95 parts by weight, and the like.

The type of the fluororesin included in the primer layer may be the same as or different from that of the fluoropolymer of the surface layers 20 and 30 formed on the top layer, and may further include various other additives as needed.

On the other hand, the manufacturing method of the transparent back sheet 100 according to the present application includes the step of forming the surface layers 20 and 30 on the substrate 10 according to the first aspect of the present application. In forming the surface layers 20 and 30, a transparent pigment is included. That is, in forming the surface layers 20 and 30, a resin composition including a base resin (a fluorine resin or the like) and a transparent pigment is used. At this time, the surface layers 20 and 30 can be formed by coating the resin composition or by bonding a resin film formed from the resin composition.

Further, in forming the surface layers 20 and 30, the types (components) and the content of the base resin and transparent pigment used are as described above. Specifically, as described above, the base resin may include a fluorine resin. The amount of the transparent pigment may be 0.1 to 30 parts by weight or 0.1 to 10 parts by weight based on 100 parts by weight of the base resin.

The method of manufacturing the transparent back sheet 100 according to the present application is characterized by comprising a first step of forming a first surface layer 20 on one side of the substrate 10 and a second step of forming a second surface layer 20 on the side of the substrate 10 And a second step of forming a second surface layer 30 on the other side of the substrate 10. At this time, at least one step selected from the first step and the second step is formed by including a transparent pigment. That is, the first surface layer 20 and the second surface layer 30 are formed by using a resin composition including a base resin (such as a fluorine resin) and a transparent pigment. The concrete formation method is as described for the first embodiment.

According to the transparent back sheet 100 of the present application described above, it is possible to prevent the mounting structure from rising in temperature while maintaining transparency. And weatherability is improved. Referring to FIG. 3, a case where a transparent paint having light sorting characteristics is included in the first surface layer 20 will be described as an example.

3, when light is incident on the surface of the transparent back sheet 100, ultraviolet light (UV) is absorbed in the first surface layer 20 containing the transparent pigment, infrared light (IR) is reflected, Is transmitted. Therefore, the infrared rays IR are not transmitted to the back surface of the back sheet 100 due to the reflection of the infrared rays IR, thereby preventing an internal temperature rise of the installation structure (building). The absorption of ultraviolet rays (UV) prevents the yellowing of the base material 10, such as PET, which can be generated by irradiation of ultraviolet rays (UV), and has excellent weather resistance. In addition, transparency can be ensured by transmission of visible light, which can be usefully applied to transparent solar cell modules, for example. In addition, since ultraviolet rays (UV) are absorbed by the transparent pigment, it is possible to exclude the step of adding a separate UV absorbent as in the prior art.

On the other hand, the optical module according to the present application includes the transparent back sheet 100 of the present application as described above. The optical module according to the present application includes any structure including the transparent back sheet 100 of the present application as described above. The optical module according to the present application is not limited as long as it uses light (for example, solar light), and can be selected from, for example, a photovoltaic module, a concrete example, a solar cell module and the like.

4 shows an exemplary form of an optical module according to the present application. The optical module shown in Fig. 4 is an example of a solar cell module.

4, an optical module according to the present application includes, in accordance with an exemplary embodiment, a front transparent substrate 210, an encapsulant layer 220, a solar cell C, and a transparent back sheet (100).

The front transparent substrate 210 may be provided so as to provide a light receiving surface while protecting the front side (upper side in the figure) of the solar cell C. The front transparent substrate 210 may be any light transmissive substrate having excellent light transmittance. The front substrate 210 is a transparent substrate favorable for light incidence, and may be selected from a rigid substrate such as glass (for example, tempered glass) or a transparent plastic plate.

The encapsulant layer 220 encapsulates the solar cell C and may include a front encapsulant layer 221 and a back encapsulant layer 222. At this time, as shown in FIG. 4, the solar cell C is packed and fixed between the front encapsulant layer 221 and the rear encapsulant layer 222.

The sealing material constituting the sealing material layer 220 is not limited. The encapsulant constituting the encapsulant layer 220 is not particularly limited as long as it has adhesiveness and insulation properties, and may include, for example, a conventionally used EVA resin, that is, an ethylene-vinyl acetate copolymer. As the sealing material constituting the encapsulant layer 220, resins other than the EVA resin may be used. As the sealing material constituting the sealing material layer 220, for example, a polyolefin-based sealing material or the like may be used. More specifically, polyolefins such as polyethylene, polypropylene, ethylene / propylene copolymer, and ethylene / propylene / butadiene copolymer can be used.

The plurality of solar cells C are arranged in the encapsulant layer 220. That is, the solar cell C is packed and fixed (encapsulated) in a state where a plurality of the solar cell C are arranged on the front encapsulant layer 221 and the rear encapsulant layer 222. The solar cells C are electrically connected to each other.

In the present application, the solar cell (C) is not particularly limited. The solar cell C may be selected from a crystalline solar cell and a thin film solar cell. In addition, in the present application, the solar cell C includes a front electrode type, a rear electrode type, and a combination thereof.

The transparent back sheet 100 is bonded to the bottom of the encapsulant layer 220. More specifically, the first surface layer 20 of the transparent back sheet 100 is adhered to the lower surface of the back sealing material layer 222. At this time, the rear sealing material layer 222 and the first surface layer 20 may be bonded to each other through thermal lamination (thermal fusion bonding) or an adhesive. The adhesive is not particularly limited, and one or more adhesives selected from, for example, acrylic, urethane, epoxy and polyolefin resins may be used.

According to a specific form of the present application, the back sealing material layer 222 and the first surface layer 20 may be bonded by thermal lamination. The thermal lamination may be conducted at a temperature of, for example, 90 ° C to 230 ° C, or 110 ° C to 200 ° C for 1 minute to 30 minutes, or 1 minute to 10 minutes, but is not limited thereto.

According to a more specific form, the manufacture of the optical module includes a front substrate 210, a front encapsulant layer 221, an electrically connected solar cell C, a back encapsulant layer 222, and a transparent back sheet 100, Are successively laminated, and then heat lamination is carried out while vacuum-sucking them integrally.

In addition, the optical module according to the present application may further include a rear transparent substrate (not shown) according to an exemplary embodiment. The rear transparent substrate may be selectively included depending on the type of the optical module and the installation location. For example, the front transparent substrate 210 may be the same as the front transparent substrate 210. The rear transparent substrate may be selected from a rigid substrate such as a glass substrate (e.g., tempered glass) or a transparent plastic substrate.

Hereinafter, examples and comparative examples of the present application will be exemplified. The following embodiments are provided by way of example only to aid understanding of the present application, and thus the technical scope of the present application is not limited thereto.

[Example]

A transparent PET film was prepared, and surface layers (first surface layer and second surface layer) were formed on both sides of the PET film. The PET film was used by surface coating with an oxazoline primer. At this time, the surface layer was formed by coating a resin composition containing 5 parts by weight of a light selective transparent pigment to 100 parts by weight of polyvinylidene fluoride (PVDF). And the optical selectivity transparent pigment was used as the inorganic pigments including the mica (mica), titanium oxide, zinc oxide and tin oxide, Iritec ^® 9870 [Merck products.

[Comparative Example]

In comparison with the above examples, the same operation was performed except that TiO2 was used instead of the light selective transparent pigment. Specifically, a surface layer was formed on both surfaces of a transparent PET film, and a resin composition containing 5 parts by weight of TiO ₂ with respect to 100 parts by weight of polyvinylidene fluoride (PVDF) was used as the resin composition constituting the surface layer.

The transparent back sheet specimens according to each of the examples and comparative examples were evaluated for light transmittance according to wavelength. The results are shown in the attached FIG.

As shown in FIG. 5, in the case of the transparent backsheet according to the embodiment, the transmittance for visible light (between about 400 nm and 700 nm) is very high while effectively absorbing ultraviolet light (about 400 nm or less). Particularly, it can be seen that the light transmittance is very low in the wavelength range of infrared rays (700 nm or more). On the contrary, in the case of the transparent back sheet according to the comparative example, the transmittance for visible light (between about 400 nm and 700 nm) is somewhat low, and the light transmittance is highly evaluated especially at the wavelength range of infrared (700 nm or more).

Accordingly, when the transparent back sheet according to the embodiment of the present application is applied to a window or a greenhouse, it is possible to effectively prevent (reflect) the infrared ray (IR) have.

10: substrate 20, 30: surface layer
100: back sheet 210: front transparent substrate
220: encapsulating material layer C: solar cell

Claims (19)

Front transparent substrate;
An encapsulant layer formed on the front transparent substrate;
A solar cell encapsulated in the sealing material layer; And
And a transparent back sheet formed on the sealing material layer,
The transparent back sheet comprises: a substrate; A surface layer including a first surface layer formed on one side of the substrate and a second surface layer formed on the other side of the substrate; And a transparent pigment which absorbs ultraviolet rays and reflects infrared rays,
Wherein the first surface layer is bonded to the sealing material layer,
Wherein the transparent pigment is contained in one or both of the first surface layer and the second surface layer.
delete delete The method according to claim 1,
Wherein the substrate is selected from the group consisting of a polyethylene terephthalate (PET) film, a polyethylene naphthalate (PEN) film, a polybutylene terephthalate (PBT) film, an acrylic film, a polyolefin film, a polyamide film and a polyurethane film.
The method according to claim 1,
Wherein the first surface layer or the second surface layer comprises a fluorine-based resin.
The method according to claim 1,
And a primer layer formed between the substrate and the first surface layer or the second surface layer.
The method according to claim 6,
Wherein the primer layer comprises the transparent pigment.
The method according to claim 6,
Wherein the primer layer comprises an oxazoline group-containing compound.
6. The method of claim 5,
Wherein the first surface layer or the second surface layer comprises 0.1 to 10 parts by weight of a transparent pigment based on 100 parts by weight of the fluororesin.
The method according to claim 1,
Wherein the transparent pigment is an inorganic pigment containing aluminum (Al), titanium (Ti), zinc (Zn) and tin (Sn)
The method according to claim 1,
Wherein the transparent pigment is an inorganic pigment comprising mica, titanium oxide, zinc oxide and tin oxide.
delete A first step of forming a first surface layer on one side of the substrate; And
And a second step of forming a second surface layer on the other side of the substrate,
Wherein the at least one step selected from the first step and the second step includes:
Base resin; And
The method of manufacturing an optical module according to claim 1, wherein the optical module is formed using a resin composition containing a transparent pigment that absorbs ultraviolet rays and reflects infrared rays.
14. The method of claim 13,
Wherein the base resin comprises a fluorine-based resin.
14. The method of claim 13,
Wherein the resin composition comprises 0.1 to 10 parts by weight of a transparent pigment based on 100 parts by weight of the base resin.
14. The method of claim 13,
Wherein the transparent pigment is an inorganic pigment containing aluminum (Al), titanium (Ti), zinc (Zn) and tin (Sn)
14. The method of claim 13,
Wherein the transparent pigment is an inorganic pigment comprising mica, titanium oxide, zinc oxide and tin oxide.
delete delete

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