TW202025616A - Luminescent solar concentrator - Google Patents

Abstract

The invention presents a luminescent solar concentrator, comprising a diffraction optical layer inserted between a first transparent substrate with a luminescent layer deposited on its top and a second transparent substrate. The surface of the diffraction optical layer has a microstructure with a size comparable to the wavelength of incident light. A solar panel module is attached to the edges of the first transparent substrate and the second transparent substrate. The incident light is first absorbed by the luminescent layer on the top of the first transparent substrate and then re-emits light at a longer wavelength in a random direction. Some of the re-emitting light is guided to the solar panel at the edge of the substrates by total internal reflection. Insertion of the diffractive optical layer in between two substrates will reduce the times for the guided light to re-enter the luminescent layer and reduce the re-absorption effect. As a result of less loss in the light-guiding process, the device will have more light energy to be converted into the electric energy and will be highly competitive in the market.

Description

Fluorescent Solar Concentrator

The present invention relates to a fluorescent solar concentrator, which refers to a type of optical diffractive interlayer that can deflect the direction of the penetrating light, reduce the number of total reflections required when the light is guided to the side, reduce the reabsorption effect, and reduce the concentrator The technical field of energy loss.

In recent years, the use of natural energy has attracted much attention. Solar energy has the advantages of inexhaustible, inexhaustible, clean and pollution-free environmental protection. It has considerable advantages in human life, industrial production, commercial addition, or national defense and military. Application category. Since the sun and the earth are in relative motion for a long time, effective solar energy harvesting must be tracked to the sun, so as to obtain the maximum sunshine at any time, so that the solar energy can receive the highest amount. However, the sun tracking device installed in the conventional solar energy harvesting technology, device, or system is mostly a mechanical structure, and the sun tracking and pointing to the sun are achieved through the rotation or movement of the mechanism components. However, the sun tracking device is inevitably bulky, resulting in high construction costs, and requires additional electric energy to drive it, which will inevitably lead to the disadvantage of lowering the efficiency of actual solar energy harvesting; for the application of solar power generation, the machinery of the sun tracking device The structure needs to consume a large part of the electricity converted from solar energy, and the remaining available electricity is greatly reduced. Furthermore, the existing solar panels are bulky and can only be placed on the roof or the ground, which not only takes up space but is also unsightly.

In view of this, the development of fluorescent solar concentrators (LSC) was born accordingly. Fluorescent solar concentrators consist of a glass or plastic waveguide, which defines the surface with a layer doped with a height that is usually called fluorescent group In the body of the concentrator of the excited light element, the fluorophore absorbs sunlight (both scattered and incident sunlight), and re-emits it with fluorescence or phosphorescence at a longer wavelength, and the emitted light is internally integrated The reflection is guided to the edge of the waveguide and converted into electrical energy along the long and narrow small-area photovoltaic cells on the side or peripheral surface of the waveguide. By appropriately selecting the concentration and optical properties of the fluorophores in the luminescent layer, the desired transparency and color can be designed; because fluorophores can convert incident light from different directions into a pattern with equal probability in all directions It emits fluorescent light with a longer wavelength, so it does not need a sun tracking device and can be combined with building glass; therefore, fluorescent solar concentrators need to track the light source than known, and are based on the geometric configuration to concentrate solar radiation. Operating system, more practical equipment.

Continuing with the existing fluorescent solar concentrator, as shown in Figure 1, the luminescent solar concentrator includes a glass 10 on which a fluorescent layer 12 is provided, and a solar cell module is provided on the side of the glass 10 14. When the fluorescent group in the fluorescent layer 12 absorbs sunlight and converts the wavelength, before the light reaches the solar cell module 14 at the edge of the collector body, the light in the glass 10 needs to undergo multiple total reflections to guide the light to the solar cell module In 14 the light energy is converted into electric energy. However, when the light travels, it will be reabsorbed by the fluorophores in the fluorescent layer 12, resulting in light loss. The range marked a in the figure is because the fluorophores in the fluorescent layer 12 generally absorb and emit There are overlapping sections between the frequency spectra, so that the emitted light may have a chance to be reabsorbed when it returns to the phosphor layer 12. The re-absorption phenomenon will lead to light loss and low light collection efficiency, and the larger the area of the fluorescent solar concentrator, the more serious the light loss will be. Therefore, how to reduce the light loss caused by light reabsorption is an urgent problem to be solved.

In view of this, the present invention addresses the above-mentioned shortcomings of the prior art and proposes a fluorescent solar concentrator to effectively overcome the above-mentioned problems.

The main purpose of the present invention is to provide a fluorescent solar concentrator, which is characterized by using a light wave diffraction interlayer to reduce the number of total reflections required for light to reach the side, reduce the loss of reabsorption effect, and improve the efficiency of solar cell power generation.

The secondary objective of the present invention is to provide a fluorescent solar concentrator, which uses diffractive optics to generate a light deflection effect to increase the incident angle of the light guide, so as to reduce the number of total reflections required for the light source to reach the solar panel module on the side , Can reduce the light loss problem of re-absorption and increase the light collection efficiency.

Another object of the present invention is to provide a fluorescent solar concentrator, which can be integrated on building windows, roof skylights, any wall that can be irradiated with sunlight, outdoor devices with transparent surfaces, etc., without The sun tracking device can also be combined with building glass, which has a great market competitive advantage. Because of the reduction of the reabsorption effect, our proposed fluorescent solar concentrator can be applied to a larger area of building glass compared to the traditional fluorescent solar concentrator.

To achieve the above objective, the present invention provides a fluorescent solar concentrator, which includes a first transparent substrate, a second transparent substrate, a fluorescent layer, a diffractive optical layer, and a solar panel module. The first transparent substrate is arranged on the second transparent substrate, and the phosphor layer is arranged on the first transparent substrate. It receives the incident light of sunlight and converts it into fluorescent light of longer wavelength for uniform radiation, that is, the incident light from different directions It is converted into fluorescent light with a longer wavelength radiated with equal probability in all directions; the diffractive optical layer is arranged between the first transparent substrate and the second transparent substrate to deflect the direction of the fluorescent light passing through the diffractive optical layer, The surface of the diffractive optical layer has a microstructure equivalent to the wavelength of the light wave of the size, and the structural dimension of the microstructure is about micrometers. The light guide direction is deviated from the normal direction for spatial phase modulation, which can reduce the light guide side. The number of total reflections reduces the chance of light being absorbed again when entering the fluorescent layer; the solar panel module is arranged on the side of the first transparent substrate and the second transparent substrate, and the light source is deflected according to the fluorescent direction of the diffractive optical layer Guide to the side and collect light energy to convert it into electrical energy.

Among them, the microstructure is a one-dimensional (striped score) or two-dimensional phase-modulated grating microstructure, including binary concave-convex microstructures or stepped microstructures. The microstructure is designed with a scale equivalent to the wavelength of light, which can change The deflection direction of the emitted light to achieve the purpose of the preset light traveling direction.

Among them, the diffractive optical layer can be integrated into the first transparent substrate or the second transparent substrate. The microstructure is manufactured by laser engraving, photosensitive material (such as photoresist) imaging or thermoforming technology, and laser engraving Or chemically etch the microstructure on the lower surface of the first transparent substrate or the upper surface of the second transparent substrate, whether the diffractive optical layer is integrated on the lower surface of the first transparent substrate or the upper surface of the second transparent substrate Since the diffractive optical layer is located between the first transparent substrate and the second transparent substrate, the light-collecting effect can be achieved.

Wherein, the diffractive optical layer is a thin film or plastic sheet, which is arranged between the first transparent substrate and the second transparent substrate.

Among them, the material of the phosphor layer is organic phosphor or inorganic phosphor. The phosphor layer absorbs the invisible light of a specific wavelength in sunlight and converts it into longer wavelength light. Because the material of the phosphor layer does not absorb all Visible light spectrum, so through the fluorescent layer can maintain the substrate in certain colors and have transparency.

Among them, the fluorescent solar concentrator further includes a reflective layer arranged on the bottom of the second transparent substrate. The reflective layer plays the role of a reflective grating. Its design can make the reflection angle greater than the incident angle, which can further reduce the number of total reflections. Improve light collection efficiency.

Among them, the transparent substrate is a transparent glass substrate, a transparent plastic substrate or a transparent acrylic substrate.

In response to the environmental requirements of "energy saving and carbon reduction", the present invention is eager to improve and innovate, and after years of painstaking research, a fluorescent solar concentrator has been developed. Since one of the main difficulties in the commercialization of solar concentrators lies in its high self-absorption rate (Rates of Self-absorption), that is, the concentrator itself absorbs most of the light in the solar spectrum, but not The light energy guided by total reflection is transmitted to the solar cell. Therefore, the invention uses the special microstructure design of the diffractive optical element to reduce the self-absorption loss of the light guide, which is actually an important breakthrough in sunlight collection technology. The fluorescent solar concentrator of the invention can be manufactured according to requirements. The use of large-area solar windows for buildings not only improves the efficiency of energy use, but also promotes the development of colorful energy, but also fulfills the responsibility of saving the earth on which mankind depends on living. It can become the best energy-saving appeal of the new generation. By.

Please refer to Figure 2, which is a schematic diagram of the structure of the fluorescent solar concentrator of the present invention. The fluorescent solar concentrator includes a first transparent substrate 20, a second transparent substrate 22, a fluorescent layer 24, a diffractive optical layer 26, and a solar panel module 28. The second transparent substrate 22 is provided on the first transparent substrate 20, the phosphor layer 24 is provided on an upper surface of the first transparent substrate 2, and the diffractive optical layer 26 is provided between the first transparent substrate 20 and the second transparent substrate 22, The solar panel module 28 is arranged on the sides of the first transparent substrate 20 and the second transparent substrate 22. Among them, the fluorescent layer 24 receives one of the incident light sources of sunlight, and the material of the fluorescent layer 24 is organic phosphor or inorganic phosphor; when the incident light source of sunlight irradiates the fluorescent layer 24, the fluorescent layer The fluorescent material of 24 absorbs incident photons and re-radiates longer-wavelength photons. The fluorescent material of the present invention allows selection of ultraviolet and near-infrared absorption and conversion into other wavelengths of infrared. The fluorescent layer 24 converts the incident light source into fluorescent light with a longer wavelength and radiates it uniformly. The fluorescent light is scattered to the diffractive optical layer 26 in the first transparent substrate 20. The diffractive optical layer 26 transmits the fluorescent light into In the second transparent substrate 22, at the same time, the surface of the diffractive optical layer 26 has a microstructure equivalent to the wavelength of the light wave of the size, and the structure of the microstructure is about a micrometer scale, which deflects the direction of fluorescence passing through the diffractive optical layer 26 In order to perform spatial phase modulation, the light wave is diffracted for total reflection. When the fluorescent light is scattered through the first transparent substrate 20 and then passes through the microstructure on the surface of the diffractive optical layer 26, the light is deflected to deviate from the normal direction. That is to increase the angle of the incident angle and emit the light source at an angle greater than the incident angle, which can reduce the total reflection times required for the light to reach the side, and reduce the light loss of the light source absorbed by the fluorescent layer 24 again. Finally, the light will be guided to the solar panel modules 28 on the sides of the first transparent substrate 20 and the second transparent substrate 22 to collect light after a small number of total reflections, and store light energy and convert it into electrical energy.

Please refer to Figures 3A to 3B at the same time, which are respectively a schematic diagram of the concave-convex microstructure and a schematic diagram of the stepped microstructure on the diffractive optical layer of the present invention. Of course, the microstructure can also be a one-dimensional striped phase modulation grating microstructure ( Not shown in the picture). Based on the theory of light wave diffraction, the optical path of each point in the microstructure can be calculated, so that the diffractive optical layer 26 can change the wavefront of the incident light source to produce the expected wavefront distribution. It is worth noting that the diffractive optical layer 26 The scale of the microstructure must be equivalent to the light wavelength (about micrometer scale), and the novel diffractive optical layer 26 of the present invention is designed to modulate the light phase in one or two dimensions to achieve the deflection of the direction of the emitted light.

Wherein, the diffractive optical layer 26 can be integrated with the first transparent substrate 20, and the microstructures can be engraved on the lower surface of the first transparent substrate 20 by laser, and then the second transparent substrate is provided on the first transparent substrate 20; or The optical layer 26 can be integrated with the second transparent substrate 22, and the microstructures can be engraved on the upper surface of the second transparent substrate 22 by laser, and then the first transparent substrate is disposed on the second transparent substrate 20, regardless of the diffractive optical layer How the 26 is bonded to the lower surface of the first transparent substrate 20 or the upper surface of the second transparent substrate 22 is located between the first transparent substrate 20 and the second transparent substrate 22. Therefore, after the incident light source is scattered by the fluorescent layer, the fluorescent light enters the first transparent substrate 20 first, and then passes through the microstructure of the diffractive optical layer 26 to perform spatial phase modulation to deflect the fluorescent direction, and finally The deflected fluorescent light enters the second transparent substrate 22, and the direction of the emitted light is further deviated from the normal direction by the diffractive optical layer 26 in a penetrating manner, which reduces the number of total reflections required for the light to reach the side and reduces The loss of reabsorption effect can effectively improve the efficiency of light collection. Wherein, the diffractive optical layer 26 can also be a film sheet or a plastic sheet, which is disposed between the first transparent substrate 20 and the second transparent substrate 22.

In addition to using the diffractive optical layer 26 to improve the efficiency of light collection, please refer to FIG. 4 again, which is another schematic diagram of the structure of the fluorescent solar concentrator of the present invention. The fluorescent layer 24 is provided on an upper surface of the first transparent substrate 2, the diffractive optical layer 26 is provided between the first transparent substrate 20 and the second transparent substrate 22, and the bottom surface of the second transparent substrate 22 is provided with a reflective layer 30. The solar panel module 28 is arranged on the sides of the first transparent substrate 20 and the second transparent substrate 22. When the incident light source of sunlight irradiates the fluorescent layer 24, the fluorescent layer 24 converts the incident light source into fluorescent light with a longer wavelength to radiate uniformly, and at the same time, the fluorescent light is scattered and incident on the first transparent substrate 20 and the second transparent substrate 20 and the second transparent substrate. The diffractive optical layer 26 in the transparent substrate 22 deviates the light from the normal through the diffractive optical layer for spatial phase modulation. The light source after the fluorescent direction is deflected is guided to the second transparent substrate 22, and then the reflective layer 30 is used as a reflection Type grating to further deviate the light from the normal line, so that the reflection angle of the light source is greater than the incident angle to be guided to the solar panel module; this can again reduce the number of total reflections required for the light to be directed to the solar panel module 28, which can further improve the collection Light efficiency. Among them, the first transparent substrate 20 and the second transparent substrate 22 are transparent glass substrates, transparent plastic substrates or transparent acrylic substrates. As long as they use light-transmitting materials, they belong to the scope of the patent protection. Therefore, the diffractive optical layer 26 and the reflective layer 30 generate a double light deflection effect to greatly increase the total reflection angle, and deflect the light to reduce the number of total reflections required for the light source to reach the solar panel module 28 on the side. The diffractive optical layer 26 is optically a transmissive phase modulation grating, and the reflective layer 30 is a reflective phase modulation grating; its analogy is like a convex lens and a concave mirror having similar functions, but the convex lens is used to condense the transmitted light, while the concave mirror is used To gather reflected light. Therefore, the present invention can be applied to high-rise buildings with many windows, skylights of houses or car windows. It not only collects solar energy, but does not hinder the transparency and affect the human eye to view the outdoor scene, so that ordinary windows are transformed into Windows that can generate electricity are extremely industrially usable.

In summary, the present invention uses a novel diffractive optical layer design, especially the microstructure in micrometer scale and the pre-wavefront distribution designed by calculating the optical path of each light point, so that light waves are diffracted and light is totally reflected. , Can effectively gather sunlight and improve the efficiency of solar cell power generation. Or it can be combined with the double light wave diffraction of the diffractive optical layer and the reflective layer and increase the total reflection angle to deflect the light to reduce the number of total reflections required for the light source to reach the solar panel module on the side, and not only reduce the light loss of reabsorption The problem can increase the light collection efficiency. Furthermore, the present invention can be integrated in building windows, roof skylights, any wall that can be irradiated with sunlight, outdoor devices with transparent surfaces, etc., through light wave diffraction and increasing the reflection angle can effectively improve the concentration Light efficiency, because the solar panel modules are designed in strips and installed on the side of the transparent substrate to convert electrical energy, it can make people unable to feel the existence of fluorescent solar concentrators. It is integrated into modern buildings and automotive products. It does not take up space but also has the advantages of beautiful appearance. It not only saves the extra equipment cost of the existing solar panels that require a large area, the installation space required and the unsightly problems caused by the equipment, but also increases the application flexibility, which is extremely competitive in the market. .

Only the above are only preferred embodiments of the present invention, and are not used to limit the scope of implementation of the present invention. Therefore, all equivalent changes or modifications made in accordance with the characteristics and spirit of the application scope of the present invention should be included in the scope of the present invention.

10: Glass 12: Fluorescent layer 14: Solar cell module 20: First transparent substrate 22: Second transparent substrate 24: Fluorescent layer 26: Diffraction optical layer 28: Solar panel module 30: Reflective layer

Figure 1 is a schematic diagram of the structure of a prior art luminous solar concentrator. Figure 2 is a schematic diagram of the structure of the fluorescent solar concentrator of the present invention. Figure 3A is a schematic diagram of the concave-convex microstructure on the diffractive optical layer of the present invention. Figure 3B is a schematic diagram of the stepped microstructure on the diffractive optical layer of the present invention. Fig. 4 is a schematic diagram of another structure of the fluorescent solar concentrator of the present invention.

20: The first transparent substrate

22: second transparent substrate

24: Fluorescent layer

26: Diffraction optical layer

28: Solar panel module

Claims (8)

A fluorescent solar concentrator, comprising: a first transparent substrate; a second transparent substrate arranged on the first transparent substrate; a fluorescent layer arranged on the first transparent substrate to convert incident light into The fluorescent light with a longer wavelength is radiated uniformly; a diffractive optical layer is arranged between the first transparent substrate and the second transparent substrate to deflect the direction of the fluorescent light passing through the diffractive optical layer, The surface of the diffractive optical layer has a microstructure corresponding to the wavelength of the light wave of the size for spatial phase modulation; and a solar panel module is arranged on the sides of the first transparent substrate and the second transparent substrate, based on the diffraction The light source after the fluorescent direction of the optical layer is deflected is guided to the side and collects light energy to convert it into electrical energy. The fluorescent solar concentrator according to claim 1, further comprising a reflective layer disposed on the bottom of the second transparent substrate. The reflective layer serves as a reflective grating so that the reflection angle of the light source is greater than the incident angle. To the solar panel module. The fluorescent solar concentrator according to claim 1, wherein the microstructure is a one-dimensional (striped score) or two-dimensional phase-modulated grating microstructure, including a binary concave-convex microstructure or a stepped microstructure. The fluorescent solar concentrator according to claim 1, wherein the microstructure is manufactured by laser engraving, photosensitive material imaging or thermoforming technology. The fluorescent solar concentrator according to claim 1, wherein the diffractive optical layer is integrated with the first transparent substrate or the second transparent substrate, and the microstructure is engraved or chemically etched on the first transparent substrate. The lower surface of a transparent substrate or the upper surface of the second transparent substrate. The fluorescent solar concentrator according to claim 1, wherein the diffractive optical layer is a thin film or a plastic sheet. The fluorescent solar concentrator according to claim 1, wherein the material of the fluorescent layer is organic fluorescent powder or inorganic fluorescent powder. The fluorescent solar concentrator according to claim 1, wherein the transparent substrate is a transparent glass substrate, a transparent plastic substrate or a transparent acrylic substrate.

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