Photovoltaic modules with a desired appearance

Abstract

The present invention provides a photovoltaic module having a desired appearance. The module comprises at least one solar cell having a black or dark surface portion. The module further comprises a material layer positioned over the black or dark surface portion. The material layer has a material portion that is brighter in color or appearance than the black or dark surface portion. The material portion has transmittance to visible light depending on the composition and / or thickness of the material portion. The material layer is at least mostly transparent to light in the regions between the material portions. A visible layer is positioned over the material layer and comprises at least one of an image, a pattern, or a color. The thickness, composition, and / or lateral coverage of the material portion of the material layer are selected according to the desired contrast and / or the darkness, brightness, or color of the desired appearance feature of the photovoltaic module.

Description

Technology Field

[0001] The present disclosure relates to a photovoltaic module having a desired appearance, and, in particular but not exclusively, to a photovoltaic module having a visible layer comprising an image or a visible feature. Background Technology

[0002] Photovoltaic modules convert incident sunlight into electricity and are typically installed on building rooftops, side walls, or various other locations (e.g., traffic islands to power traffic signs). Since the active surface of the solar cells, which are usually located beneath a transparent protective panel, has a black or dark appearance, the surface of the photovoltaic module appears black or dark overall.

[0003] To improve the visual appearance of photovoltaic modules, it has been conventionally proposed to print images or structures on such modules. However, such prints or structures reduce the transmissivity of sunlight. As a result, the amount of sunlight received by the solar cell decreases, and consequently, the electrical output of the photovoltaic module also decreases. The problem to be solved

[0004] The present invention provides a technical advancement. means of solving the problem

[0005] The present invention relates to a photovoltaic module having a desired appearance in a first aspect, wherein the photovoltaic module comprises:

[0006] At least one solar cell having a black or dark surface portion;

[0007] A material layer positioned over a black or dark surface portion of at least one solar cell, wherein the material layer has a material portion that is brighter in color or appearance than the black or dark surface portion of the at least one solar cell, wherein the material portion has a transmittance to visible light that depends on the composition and / or thickness of the material portion, and the material layer is at least mostly transparent to light in the region between the material portions; and

[0008] A visible layer located on the above material layer and comprising at least one of an image, a pattern, or a color; comprising

[0009] The present invention provides a photovoltaic module characterized in that the thickness, composition, and / or lateral coverage of the material portion of the material layer is selected according to the desired contrast and / or the darkness, brightness, or color of the features of the desired appearance of the photovoltaic module.

[0010] At least one solar cell can be provided in the form of a conventional photovoltaic module.

[0011] The material layer may comprise a plurality of islands having any suitable shape or size, and in one particular embodiment, the material portion is a dot such as a printed dot having a regular or irregular shape. The dots may be very small so as not to be distinguishable with the naked eye. The dots forming the array may have any suitable color brighter than the black or dark appearance of the black or dark surface portion of at least one solar cell, and in one particular embodiment, the dots exhibit a white appearance if they have a suitable composition such as sufficient thickness and at least largely opaque to visible light. The dots may be formed by a printing process such as digital printing.

[0012] The dots may have a local thickness depending on the darkness or brightness and / or desired contrast of the features of the desired appearance of the photovoltaic module. The thickness of the dots may vary within the material layer. In one specific embodiment of the present invention, at least a portion of the dots is sufficiently thin to have a transmittance to visible light that is dependent on the thickness of the dots. For example, the dots may have a thickness in the range of 0-10 µm or 0-5 µm depending on the desired local transmittance. When the dots have a thickness greater than several millimeters, such as when the dots are greater than 5 µm, the dots locally block at least most of the incident visible light. On the other hand, when the thickness of the dots is 0 to 5 µm, the dots exhibit a gray or even black or dark appearance (for a thickness of nearly 0 µm) as they are positioned over the black or dark surface portion of at least one solar cell. The dots may be formed using a digital printing process. Desired variations in the thickness of the dots within the material layer can be achieved through a series of printing processes. In a continuous printing process, thickness can be increased by selectively printing additional dots on top of the dots formed in the previous process. The total (cumulative) print thickness of each dot is determined by whether a dot is formed in each printing process.

[0013] Alternatively or additionally, the dot may have a composition determined by the desired contrast and / or the darkness or brightness of the features of the desired appearance of the photovoltaic module. In this case, the dot may have a transmittance that depends on its composition. For example, the dot may include opaque ink, such as white ink, and transparent ink. Depending on the desired local transmittance, the dot may have a composition of 0-20%, 20-40%, 40-60%, 60-80%, or 80-100% transparent ink, with the remainder being opaque ink. Accordingly, the transmittance of the dot is determined by its composition. The dot may have a thickness of 0-5 µm or more. By varying the composition of the dot, the degree of blackness (or darkness) of the dot can be controlled when the dot is positioned over a black or dark surface portion of at least one solar cell.

[0014] The present invention enables black or dark features to be realized with a desired contrast by providing dots having a selected thickness or composition within a material layer. Accordingly, it provides the advantage that there is no need to print black or dark features separately when an image is formed within a visible layer above the material layer. In one specific embodiment, even if features of the image visible out of the photovoltaic module appear black or dark, the visible layer includes the printed image formed within the visible layer without using a color scheme. For example, the image may be printed using only cyan, magenta, and yellow.

[0015] In the printing process, black significantly reduces the transmittance of visible light, thereby becoming a factor that lowers the conversion efficiency of the photovoltaic module. In an embodiment of the present invention, by forming an image without using black, the present invention according to the embodiment provides the effect of improving the conversion efficiency of the photovoltaic module.

[0016] Additionally, the material layer can adjust coverage (e.g., dot diameter and distance between dots) according to the desired contrast and / or the darkness or brightness of the features of the desired appearance of the photovoltaic module. Since the area between dots is at least mostly transparent to visible light, the area between dots located over a black or dark part of at least one solar cell appears black or dark. Therefore, the degree of darkness can be controlled by adjusting the dot diameter and / or the spacing between adjacent dots. Since the area between dots appears black or dark, the smaller the dots and the larger the spacing between dots, the darker the appearance appears.

[0017] In one embodiment, the dots have a diameter of approximately 100 μm, for example 50 μm to 200 μm, and the gaps between adjacent dots may be 20 to 40 μm, 40 to 60 μm, 60 to 80 μm, and 80 to 100 μm, for example 30 μm.

[0018] In one specific embodiment, the thickness and composition of the dots in the material layer and the characteristics of the visible layer image are selected such that at least most or all of the visible layer and the material layer have a transmittance greater than 0 (zero) for visible light. As mentioned above, in one embodiment, when the dots are sufficiently thick and have an appropriate composition, the dots exhibit a white appearance. However, when the thickness and composition are such that the dots appear white, the dots block a significant portion of light transmission. The inventors have observed that good and acceptable contrast in the image can already be achieved when the transmittance of the dots is increased, even in brighter color regions of the image. For example, this can be achieved by reducing the thickness of the dots to 70% or less, 50% or less, 30% or less, 20% or less, or even 10% or less relative to a reference thickness that blocks more than 90% of the visible light passing through the dots. Alternatively, the composition of the dots can be changed by increasing the content of a transparent component, such as transparent ink for forming the dots, to more than 30%, more than 50%, more than 70%, more than 80%, or even more than 90%. The inventors observed that even when the transmittance is increased to 85% of the transmittance at which the dots produce the highest quality image with the best contrast, sufficient contrast is still visible. As the transmittance increases, the conversion efficiency of the photovoltaic module becomes higher.

[0019] In one embodiment, the dot has a thickness in the range of 0 μm to 5 μm. The dot can be formed, for example, using a UV flatbed inkjet or ceramic digital printing process.

[0020] At least one solar cell may be of any suitable type and, in one particular embodiment, may be a cadmium telluride (CdTe)-based solar cell.

[0021] The visible layer may be a first visible layer located on a first main surface of at least one solar cell. Additionally, the photovoltaic module may include a second visible layer comprising at least one of a color, an image, and a pattern. The second visible layer may be located on a second main surface opposite to the first main surface of at least one solar cell, so that the first and second visible layers are visible from both sides of the at least one solar cell.

[0022] To substantially equalize the height difference of the dots and substantially fill the gaps between adjacent dots, a layer of transparent ink or varnish may be additionally formed on the material layer.

[0023] In a second aspect, the present invention provides a method for forming a photovoltaic module having a desired appearance, wherein the method comprises:

[0024] A step of providing at least one solar cell having a black or dark surface portion;

[0025] A step of forming a material layer on a black or dark surface portion of at least one solar cell, wherein the material layer has a material portion that is brighter in color or appearance than the black or dark surface portion of the at least one solar cell, wherein the material portion has transmittance to visible light according to its thickness and / or composition, and the material layer has at least mostly transmittance to light in the regions between the material portions; and

[0026] The method includes the step of forming a visible layer comprising at least one of an image, a pattern, or a color;

[0027] The present invention provides a method for forming a photovoltaic module, characterized in that the material layer is located between a black or dark surface portion of at least one solar cell and a visible layer, and the material layer forming step includes the step of selecting the thickness, composition, and / or lateral coverage of the material portion of the material layer according to the desired contrast and / or the darkness, brightness, or color of the desired appearance feature of the photovoltaic module.

[0028] The step of forming a material layer and / or the step of forming a visible layer may include a digital printing process such as digital UV printing or digital ceramic printing.

[0029] At least one solar cell can be provided in the form of a conventional photovoltaic module.

[0030] The material portion of the material layer may be a dot. In one embodiment, the dot has a diameter of approximately 100 µm, e.g., 50 µm to 200 µm, and the gap between adjacent dots has a spacing of 20 to 40 µm, 40 to 60 µm, 60 to 80 µm, and 80 to 100 µm, e.g., 30 µm. The dots may have a thickness in the range of 0 to 10 µm or 0 to 5 µm.

[0031] Forming a material layer may include selecting a desired thickness variation of dots within the material layer. Additionally, forming a material layer may include a series of printing processes, and the dot thickness may be increased by additionally printing selected dots on top of dots formed in a previous process. This method may further include a step of selecting a location where dots are to be formed in each printing process. The total (cumulative) printing thickness of each dot is determined by whether dots are formed in each printing process. Additionally, the method may include a step of applying a clear ink or varnish to fill the gaps between adjacent dots and substantially flatten the height difference caused by dots of different thicknesses.

[0032] Alternatively or additionally, forming a material layer may include selecting the composition of dots and / or a change in the composition of dots within the material layer. In this case, the dots may have transmittance depending on their composition. The dots may be formed using a composition of ink that is transparent to visible light and ink that is opaque. The selection of composition may include selecting a ratio of ink or varnish that is transparent to visible light to opaque ink. This method may further include the step of applying a transparent ink or transparent varnish to fill the gaps between adjacent dots.

[0033] In one specific embodiment, a visible layer may be formed on the surface of a transparent panel, such as a glass panel, and the step of forming a material layer may include the step of forming a material layer directly or indirectly on the visible layer. As a variation of this embodiment, a transparent conductive adhesive layer, such as indium tin oxide (ITO), may be formed on the glass panel, a visible layer may be formed on the adhesive layer, and a material layer may be formed on the visible layer.

[0034] Additionally, the above method may include the step of forming a solar cell structure on the formed material layer. This method may further include the step of placing a glass plate on the formed solar cell structure.

[0035] In an alternative embodiment, the method comprises the steps of providing a solar cell structure and forming a material layer directly or indirectly on the surface of the solar cell structure. The method may further comprise the steps of forming a visible layer directly or indirectly on the formed material layer and placing a glass plate on the formed visible layer.

[0036] The present invention can be more clearly understood from the following description of specific embodiments of the present invention. The present invention will be described with reference to the accompanying drawings. Brief explanation of the drawing

[0037] FIGS. 1 and FIGS. 2 are schematic cross-sectional views of a photovoltaic module having a desired appearance according to an embodiment of the present invention. Figure 3 is a schematic plan view of a printed dot. Figure 4 is a graph illustrating normalized transmission power as a function of normalized thickness. Figure 5 shows the light transmittance measured as a function of print color. FIG. 6 is a schematic cross-sectional view of a printed dot according to an embodiment of the present invention. FIGS. 7 and FIGS. 8 are schematic cross-sectional views of a photovoltaic module having a desired appearance according to an embodiment of the present invention. FIG. 9 is a flowchart illustrating a method for forming a photovoltaic module having a desired appearance according to an embodiment of the present invention. FIGS. 10 to 12 illustrate embodiments of the method illustrated with reference to FIG. 9. Specific details for implementing the invention

[0038] First, with reference to FIG. 1, a photovoltaic module (100) having a desired appearance according to one embodiment is described. The photovoltaic module (100) includes a glass panel (102), and a transparent adhesive layer (103), such as transparent conductive indium tin oxide (ITO), a visible layer (104), and a material layer (106) are sequentially formed thereon. The visible layer (104) includes an image, color, or pattern. The material layer (106) includes a plurality of dots having a selected thickness (typically about 0-5 μm) and a diameter generally 10-200 μm. The dots have a white appearance when sufficiently thick and are generally fine enough not to be visible to the naked eye.

[0039] In this embodiment, the visible layer (104) comprises an image printed on the dots of the material layer (106). The resolution of the image is determined by the dot density and distribution of the material layer, for example, 50 to 5000 dots per inch. The material layer (106) and the visible layer (104) are described in more detail below. The photovoltaic module (100) may further comprise a plurality of layers (108), said layers (108) may form a solar cell structure including (i) a transparent electrode layer such as indium tin oxide (ITO), (ii) an n-type semiconductor layer such as cadmium sulfide (CdS), (iii) a p-type semiconductor layer such as cadmium telluride (CdTe), and (iv) a reflective electrode such as aluminum. In this embodiment, since the layers (108) form a known conventional solar cell structure, a detailed description thereof is omitted. A polyvinyl butyral (PVB) layer is positioned on top of the solar cell layer (108), which is used to bond the final structure to the glass panel (112).

[0040] In an alternative embodiment, a visible layer (104) and a material layer (106) can be printed on the front glass panel of a conventional photovoltaic module using a PVB sheet (not shown). This embodiment is described in more detail below with reference to FIG. 6.

[0041] Solar cells and photovoltaic modules have a black or dark appearance (active surface). As described above, the dots of the material layer (106) appear white when sufficiently thick, but as the thickness of the dots decreases from 5 μm to 0 μm, they appear in a darker color (ranging from gray to black), because the dots are located on the dark or black areas of the solar cell.

[0042] Alternatively or additionally, the dot has a transmissivity dependent on its composition. In this case, the dot is formed using an ink that is transparent to visible light (e.g., Heat Resistant Clear Lacquer with heat resistance up to 800°C, MoTip, or a transparent glass-ceramic ink produced by annealing a composition of individual or metal oxide particles such as Al2O3 or SiO2) and an ink that is opaque to visible light. The ratio of the ink that is transparent to visible light to the ink that is opaque is selected to achieve a desired degree of blackness or degree of darkness.

[0043] In addition, the thickness and composition of the dots, as well as their diameter, affect the contrast and / or the darkness or brightness of the features of the desired appearance of the photovoltaic module. As visible light passes through the areas between the dots, those areas appear black or dark (the color of a conventional photovoltaic module). Consequently, when an image is formed within the visible layer on the material layer, the visible layer (104) may not necessarily contain black or dark features, because the material layer may provide dots with selected variations in thickness and diameter to make the black or dark features visible.

[0044] In this embodiment, the visible layer (104) includes a printed image formed within the visible layer (104) without using black ink, even though the features of the image may appear black or dark when viewed from outside the photovoltaic module (100). The image is printed using only cyan, magenta, and yellow. Since black ink is not used for printing, the decrease in the transmittance of visible light through the visible layer can be suppressed, and consequently, the decrease in the conversion efficiency of the photovoltaic module can be reduced. Both the material layer (106) and the dots of the visible layer (104) can be formed using a digital printing process such as digital UV printing or digital ceramic printing.

[0045] Furthermore, the inventors have confirmed that good and acceptable contrast can be maintained in an image even in bright color regions of the image when the thickness of the dot is reduced or the transmittance of the dot is increased by appropriately selecting the composition of the dot. In this embodiment, the transmittance of the dot is increased to a level of 85% compared to the case where the dot blocks transmission through the dot. This can be achieved by reducing the thickness of the dot to 15% of the minimum thickness at which the dot blocks transmission through the dot. Alternatively, the transmittance of the dot can be increased to 85% by appropriately selecting the composition of the dot (in which case the content of the transparent ink component is increased accordingly). The increase in transmittance improves the conversion efficiency of the photovoltaic module. Those skilled in the art will understand that in variations of the described embodiment, the dot may have any other suitable thickness or composition.

[0046] FIG. 2 illustrates another photovoltaic module according to one embodiment of the present invention. The illustrated photovoltaic module (150) relates to the photovoltaic module (100) illustrated with reference to FIG. 1, and similar components are given the same reference number. The photovoltaic module (150) comprises a layer (152) of transparent ink or heat-resistant transparent varnish (or lacquer), which is composed of a combination of chemicals such as, for example, acetone, propane, butane, isobutane, 2-methoxy-1-methylethyl acetate, n-butyl acetate, butan-1-ol, and xylene. The transparent ink or heat-resistant transparent varnish fills the gaps between adjacent dots and uniformly equalizes the height difference between the dots, thereby providing a plane upon which a solar cell structure (108) is formed.

[0047] Now, with reference to FIGS. 3 through 6, the dots of the material layer (106) and the visible layer (104) will be described in more detail. In this embodiment, the dots (200) have a cylindrical shape and form an array. The dots are formed using a digital printing process using a digital inkjet printer. The dots appear white when sufficiently thick, and the thickness is selected according to the desired contrast and / or the darkness or brightness of the desired appearance features of the photovoltaic module. FIG. 3 illustrates a portion of the dots of the material layer (106), and within the selected area, the dots have the same diameter. In the illustrated example, the diameter of the dots is 100 μm, and the spacing between the dots is 30 μm.

[0048] Figure 4 is a graph showing the normalized transmittance of visible light as a function of the normalized thickness of the dot. As can be seen, the transmittance decreases exponentially with increasing thickness of the dot, reaching 2% at a thickness of 4 µm, and approaches almost 0 at a thickness of 5 µm or more.

[0049] Figure 5 shows the measured transmittance of magenta, cyan, yellow, and white (thickness approximately 5 μm) printed on glass or white dots (thickness approximately 5 μm) on glass. The visible light transmittance of the white dots is 57.58%. The average transmittance of the colors printed on the glass is 90%, and the average transmittance of the colors printed on the white dots is 48.5%. Assuming that the size and distribution of the white dots are as in Figure 3 and that colors are printed in the areas between the dots as well (resulting in an average transmittance between the dots of 90%), the total average transmittance of the dot distribution shown in Figure 2 is approximately 70.5%.

[0050] FIG. 6 is a cross-sectional view of a portion of a photovoltaic module according to an embodiment of the present invention. FIG. 6 illustrates a portion of a material layer in the form of a dot (500) and a portion of a visible layer in the form of color printed on the dot (500). The illustrated dot (500) is determined according to the desired appearance of the photovoltaic module and has a diameter, thickness, and composition within a certain range. As discussed above, the material layer having the dot (500) is positioned over a dark or black area of ​​a conventional photovoltaic module, and consequently, the diameter, thickness, and composition of the dot (which determines the transmittance of the dot to visible light) determine the darkness, brightness, and contrast of a feature (e.g., an image) as seen within the visible layer.

[0051] Now, referring to FIG. 7, a photovoltaic module (600) according to one embodiment of the present invention is illustrated. The photovoltaic module (600) comprises a material layer (602) formed directly on a transparent outer panel of a conventional photovoltaic module (604) with optionally a thin adhesive layer (606) interposed therein. Alternatively, the material layer (602) may be positioned on a thin film layer (603) that is nearly transparent to visible light. A visible layer (610) is formed on the material layer (608). The visible layer (610) and the material layer (608) are similar to the visible layer (104) and material layer (106) described above with reference to FIG. 1 through 5. As described above, the thickness, composition, and coverage of the white dots of the material layer (602) are selected to achieve the desired visual appearance of the photovoltaic module (600). Then, a glass panel (612) is bonded to the structure using a PVB layer (614).

[0052] Those skilled in the art will understand that conventional photovoltaic modules are well known in the art and generally have an outer panel formed of a suitable transparent material, such as glass or a polymer material. In this embodiment, the photovoltaic module (604) includes a CdTe-based solar cell.

[0053] Now, referring to FIG. 8, a photovoltaic module (700) according to one embodiment of the present invention is illustrated. The photovoltaic module (700) is related to the photovoltaic module (600) illustrated above with reference to FIG. 6, and similar components are given by the same reference numerals. The photovoltaic module (700) comprises a conventional solar cell (702) (in this example, CdTe-based) and an additional visible layer (704), which also comprises a visible pattern or image color forming the back surface of the photovoltaic module (700). In this embodiment, the visible layer (704) is positioned over a thin white layer (706), which is in turn bonded to the solar cell (702) through a protective layer (707) and a PVB layer (78). The visible layer (704) is also bonded to an external glass panel (712) through an adhesive layer (714).

[0054] Now, with reference to FIG. 9, a method for forming a photovoltaic module having a desired appearance according to a specific embodiment of the present invention will be described. The method (800) includes the step (802) of providing a solar cell or photovoltaic module having a black or dark surface portion. In this embodiment, the step (802) includes providing a conventional photovoltaic module having a plurality of CdTe-based solar cells.

[0055] The method (800) further comprises the step (804) of forming a material layer on a black or dark surface portion of a solar cell. The material layer has a material portion that is brighter in color or appearance than the black or dark surface portion of the solar cell and has a transmittance to visible light that is dependent on the thickness of the material portion. The material layer is generally transparent to light between the material portions of the brighter color or appearance.

[0056] Additionally, the method (800) includes the step (806) of forming a visible layer on a material layer. The visible layer, in this embodiment, includes an image, but may alternatively include a pattern or a color. Forming the material layer includes selecting the thickness and / or side coverage of the material portion of the material layer according to the desired contrast and / or the darkness, brightness, or color of the features of the desired appearance of the photovoltaic module.

[0057] Now, with reference to FIG. 10, an embodiment of the method (800) is described in more detail. First, a glass pane is provided (step 1002). In this example, the thickness of the glass pane is 3 mm. A visible layer containing an image is formed on the glass pane (step 1004). The visible layer is similar to the visible layer (610) discussed with reference to FIG. 6. Then, a material layer is formed on the visible layer (step 1006). The material layer is formed using a digital printing process such as digital UV printing or digital ceramic printing. The material layer includes dots of varying thickness to achieve a desired transmittance. To this end, a series of digital printing processes is applied. In each subsequent printing process, selected dots may be printed on top of the dots formed in the previous process. Not all dots may be printed in each process, and thus thickness variations may occur due to the cumulative thickness difference between the dots. In step (1008), a layer of heat-resistant transparent ink or varnish (or lacquer) is applied to fill the gaps between the dots and to equalize the height difference between adjacent dots. The transparent ink or varnish may consist of a combination of chemicals such as, for example, acetone, propane, butane, iso-butane, 2-methoxy-1-methyl ethyl acetate, n-butyl acetate, butan-1-ol, and xylene. Subsequently, a conventional thin-film solar cell structure is formed directly or indirectly on the material layer, and a glass plate (thickness 3 mm) is attached to the final structure using a PVB layer (step 1010). Since the formation of the conventional thin-film solar cell structure is a technique known to those skilled in the art, a detailed description thereof is omitted.

[0058] Now, with reference to FIG. 11, another embodiment of the method (800) is described. First, a glass plate with a thickness of 3 mm is provided (step 1102). A visible layer containing an image is formed on the glass plate (step 1104). The visible layer is similar to the visible layer (610) discussed with reference to FIG. 6. Subsequently, a material layer is formed on the visible layer (step 1106). In this embodiment, the composition of the dots is controlled using a digital printing process. In this case, the dots are formed using a composition of ink or varnish that transmits visible light and ink that does not transmit visible light. Forming the dots involves selecting a ratio of ink or varnish that is transparent to visible light and ink that is impermeable to visible light. In step (1008), a layer of heat-resistant transparent ink or varnish (or lacquer) is applied to fill the gaps between the dots and to equalize the height difference between adjacent dots. The transparent ink or varnish (or lacquer) may be composed of a combination of chemicals such as, for example, acetone, propane, butane, isobutane, 2-methoxy-1-methylethyl acetate, n-butyl acetate, butan-1-ol, and xylene. Similar to the embodiment illustrated with reference to FIG. 10, a conventional thin-film solar cell structure is formed directly on the material layer (step 1010). Then, an additional glass panel (3 mm thick in this example) is bonded to the structure formed using a PVB sheet.

[0059] Now, with reference to FIG. 12, additional embodiments of the method (800) are described. In this embodiment, the method comprises an initial step 1202 of providing a conventional solar cell module in which a solar cell is sandwiched between glass plates (in this embodiment, each glass plate has a thickness of 3 mm). Step 1204 comprises forming an adhesive layer on one of the glass plates. Step 1206 comprises forming a material layer on the adhesive layer. The material layer is formed using a digital printing process and includes dots of varying thickness to achieve a desired transmittance. As previously described with reference to FIG. 10, this is achieved through a series of digital printing processes. In each subsequent printing process, selected dots may be printed over the dots formed in the previous process. In a variation of the described embodiment, the dots may have a composition selected to produce a desired appearance as described above with reference to FIG. 11. Step 1208 forms a visible layer containing an image on the material layer. If there is a height difference between the dots, the visible layer may have a non-flat structure, which is similar to the visible layer (610) described with reference to FIG. 6. In step 1210, a glass plate (thickness 3 mm) is bonded to the final structure using a PVB layer.

[0060] Now, a variation of the method (800) is described with reference to FIGS. 1 and 2. First, a visible layer (104) is formed on an adhesive layer (103) of a glass panel (102) using a digital printing process as described above. Subsequently, a material layer (106) is printed on the image layer (102) in the manner described above. Optionally, a layer of transparent ink or heat-resistant transparent varnish (152) (as shown in FIG. 2) is formed, and said layer fills the gaps between adjacent dots and equalizes the height difference between the dots to form a flat surface. Then, a conventional thin-film solar cell structure (108) is formed directly on the material layer (106) (Fig. 1) or on the transparent ink or heat-resistant transparent varnish (152) layer. Since the formation of such a conventional solar cell structure is a known technique to those skilled in the art, a detailed description thereof is omitted. Finally, a PVB sheet (110) is used to bond the glass panel (112) to the formed structure.

Claims

Claim 1 A photovoltaic module, wherein the photovoltaic module comprises: at least one solar cell having a black or dark surface portion; and a material layer disposed over the black or dark surface portion of the at least one solar cell and configured to provide a selectable light transmission gradient by structurally modulating the transmission of light passing through the material layer, wherein the material layer comprises a plurality of discrete material portions separated from one another by light transmission regions, wherein the material layer has a color or appearance brighter than the black or dark surface portion of the at least one solar cell and has a variable thickness, composition, and / or coverage, wherein the plurality of material portions have a visible light transmittance that depends on the composition and / or thickness of each of the plurality of material portions, and wherein the material layer is transparent to light in the regions between the plurality of material portions. A photovoltaic module comprising: a visible layer disposed on the material layer and comprising at least one of an image, a pattern, or a color; wherein the thickness, composition, and / or lateral coverage of a plurality of material portions of the material layer are selected according to the required contrast and / or the darkness, brightness, or color of a feature of the photovoltaic module, and the thickness and composition of the plurality of material portions vary throughout the photovoltaic module, and the visible layer comprises a continuous layer covering the plurality of material portions, and the visible layer is substantially continuous and has a substantially uniform thickness and composition across the plurality of discrete material portions and the light-transmitting regions between them, and the visible layer is not configured to substantially modulate light transmission to the at least one solar cell, and accordingly, modulation of visible light transmission to the at least one solar cell is provided by a change in the thickness, composition, and / or coverage of the plurality of discrete material portions. Claim 2 A photovoltaic module according to claim 1, characterized in that the material layer comprises a plurality of islands provided in a dot shape. Claim 3 A photovoltaic module according to paragraph 2, characterized in that the dots have a local thickness depending on the desired contrast and / or the darkness and brightness of the features of the photovoltaic module. Claim 4 A photovoltaic module according to paragraph 2, characterized in that the dots are thin so that the dots have a transmittance for visible light dependent on the thickness of the dots. Claim 5 A photovoltaic module according to claim 2, characterized in that at least most of the dots have a thickness within the range of 0-5㎛ and are not visible to the naked eye. Claim 6 A photovoltaic module according to paragraph 2, characterized in that the dot has a composition dependent on the desired contrast and / or the darkness or brightness of the features of the photovoltaic module. Claim 7 A photovoltaic module according to claim 6, characterized in that the dot has a transmittance dependent on the composition of the dot. Claim 8 A photovoltaic module according to claim 6, characterized in that the dots comprise opaque ink and transparent ink or varnish. Claim 9 A photovoltaic module according to claim 8, wherein the dot has a composition comprising 0-20%, 20-40%, 40-60%, 60-80%, or 80-100% of transparent ink or varnish and the remainder being opaque ink, wherein the transmittance of the dot is dependent on the composition of the dot. Claim 10 A photovoltaic module characterized by the formation of dots using a digital printing process in paragraph 2. Claim 11 A photovoltaic module according to paragraph 2, characterized in that even if the features of the printed image formed within the visible layer appear black or dark when viewed from the outside of the photovoltaic module, the visible layer does not use black and includes the printed image formed within the visible layer. Claim 12 A photovoltaic module according to claim 11, characterized in that the image is printed using only cyan, magenta, and yellow. Claim 13 A photovoltaic module according to claim 2, characterized in that the diameter of the dots in the material layer and the distance between the dots determine the coverage of the selected material layer according to the desired contrast and / or the darkness or brightness of the features of the photovoltaic module. Claim 14 A photovoltaic module according to claim 2, characterized in that the diameter of the dots is 50㎛-200㎛, and the spacing between adjacent dots is in one range of 20-40㎛, 40-60㎛, 60-80㎛, and 80-100㎛ or 30㎛. Claim 15 A photovoltaic module according to claim 2, characterized in that the thickness and / or composition of the dots in the material layer and the characteristics of the image in the visible layer are selected such that all regions of the visible layer and the material layer have a transmittance for visible light greater than 0. Claim 16 A photovoltaic module according to paragraph 2, characterized in that the thickness of the dot is 70% or less, 50% or less, 30% or less, 20% or less, or 10% or less of the minimum thickness at which the dot blocks more than 90% of the transmission of visible light through the dot. Claim 17 A photovoltaic module according to paragraph 2, characterized in that the composition of the dots is changed to a percentage amount of transparent ink for forming the dots of 30% or more, 50% or more, 70% or more, 80% or more, or even 90% or more. Claim 18 A photovoltaic module according to paragraph 2, characterized in that at least one solar cell is a cadmium telluride (CdTe) series solar cell. Claim 19 A photovoltaic module according to claim 1, wherein the visible layer is a first visible layer located on a first main surface of at least one solar cell, and the photovoltaic module further comprises a second visible layer including at least one of a color, an image, and a pattern, wherein the second visible layer is located on the opposite side of the first main surface so that the first and second visible layers are visible from both sides of at least one solar cell, and is located on the second main surface of at least one solar cell. Claim 20 A photovoltaic module according to claim 2, characterized in that a layer of transparent varnish or transparent ink is positioned on the material layer to substantially equalize the height difference of the dots and substantially fill the gap between adjacent dots. Claim 21 A method for forming a photovoltaic module, the method comprising: providing at least one solar cell having a black or dark surface portion; and forming a material layer disposed over the black or dark surface portion of the at least one solar cell and configured to provide a selectable light transmission gradient by structurally modulating the transmission of light passing through the material layer, wherein the material layer comprises a plurality of discrete material portions separated from one another by light transmission regions, the material layer has a plurality of material portions that are brighter in color or appearance than the black or dark surface portion of the at least one solar cell and have variable thickness, composition, and / or coverage, wherein the plurality of material portions have a visible light transmittance that depends on the composition and / or thickness of each of the plurality of material portions, and the material layer forms a material layer that is transparent to light in the regions between the plurality of material portions. A method for forming a photovoltaic module comprising the step of forming a visible layer on the material layer, the visible layer comprising at least one of an image, a pattern, or a color; wherein the thickness, composition, and / or lateral coverage of a plurality of material portions of the material layer are selected according to the required contrast and / or the darkness, brightness, or color of a feature of the photovoltaic module, and the thickness and composition of the plurality of material portions vary throughout the photovoltaic module, and the visible layer comprises a continuous layer covering the plurality of material portions, and the visible layer is substantially continuous and the thickness and composition are substantially uniform throughout the light-transmitting regions between the plurality of discrete material portions and the visible layer is not configured to substantially modulate light transmission to the at least one solar cell, and accordingly, modulation of visible light transmission to the at least one solar cell is provided by the change in the thickness, composition, and / or coverage of the plurality of discrete material portions. Claim 22 A method for forming a photovoltaic module according to claim 21, wherein the step of forming a material layer and / or the step of forming a visible layer includes a digital printing process such as digital UV printing or digital ceramic printing. Claim 23 A method for forming a photovoltaic module according to claim 21, characterized in that the material portion of the material layer is a dot. Claim 24 A method for forming a photovoltaic module according to claim 23, characterized in that the thickness of the dots is in the range of 0-10㎛ or 0-5㎛. Claim 25 A method for forming a photovoltaic module according to claim 23, characterized in that the diameter of the dots is 50㎛-200㎛, and the spacing between adjacent dots is in the range of 20-40㎛, 40-60㎛, 60-80㎛, and 80-100㎛ or 30㎛. Claim 26 A method for forming a photovoltaic module according to claim 23, wherein the step of forming a material layer includes a step of selecting a desired thickness change of dots within the material layer. Claim 27 A method for forming a photovoltaic module according to claim 23, wherein the step of forming a material layer includes a series of printing procedures, wherein selected dots are printed on top of dots printed in a previous procedure to increase thickness, and further including the step of selecting a position to be printed for each printing sequence. Claim 28 A method for forming a photovoltaic module according to claim 23, further comprising the step of applying a layer of transparent ink or varnish in such a way that the transparent ink or varnish fills the gaps between adjacent dots and makes the height difference arising from dots of different thicknesses substantially equal. Claim 29 A method for forming a photovoltaic module according to claim 23, wherein the step of forming a material layer includes the step of selecting the composition of dots within the material layer and / or a change in the composition of the dots. Claim 30 A method for forming a photovoltaic module according to claim 29, characterized in that the dots have a transmittance dependent on the composition of the dots. Claim 31 A method for forming a photovoltaic module according to claim 30, characterized in that dots are formed using a composition of an ink that is transparent to visible light and an ink that is impermeable to visible light. Claim 32 A method for forming a photovoltaic module according to claim 31, characterized by including the step of selecting a ratio of an ink or varnish that is transparent to visible light to an ink that is impermeable to visible light. Claim 33 A method for forming a photovoltaic module according to claim 29, further comprising the step of applying a transparent ink or varnish layer in such a way that the transparent ink or varnish fills the gaps between adjacent dots. Claim 34 A method for forming a photovoltaic module according to claim 21, characterized in that the step of forming a material layer includes the step of forming a visible layer directly or indirectly on the surface of a light-transmitting panel. Claim 35 A method for forming a photovoltaic module according to claim 34, characterized by including the step of forming a material layer directly or indirectly on a visible layer. Claim 36 A method for forming a photovoltaic module according to claim 35, further comprising the step of forming a solar cell structure on a formed material layer. Claim 37 A method for forming a photovoltaic module according to claim 36, further comprising the step of positioning a glass plate on a formed solar cell structure. Claim 38 A method for forming a photovoltaic module, characterized in that, in any one of claims 21 to 29, it comprises the steps of providing a solar cell structure and forming a material layer directly or indirectly on the surface of the solar cell structure. Claim 39 A method for forming a photovoltaic module according to claim 38, characterized by including the step of forming a visible layer directly or indirectly on a formed material layer. Claim 40 A method for forming a photovoltaic module according to claim 39, characterized by including the step of positioning a glass plate on a formed visible layer.

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