1. Field of the Invention
The present invention relates to a power generating module, and, in particular, to a power generating module having a light guiding film.
2. Description of the Related Art
The conventional solar cell module generates only a modicum of its potential power when the sunlight beam has a large incident angle. Because the sun moves during daytime, the conventional solar cell module either is disposed on an open space, such as a roof, or further includes a solar tracking system. Whichever way you look at it, the conventional solar cell module needs a very large open space to be laid out horizontally, which limits its actual implementation. In addition, the solar tracking system can ensure that the sunlight beam always illuminates the conventional solar cell module at a low incident angle to maximize the amount of power generated. However, the solar tracking system is very expensive, which results in increased manufacturing costs of the conventional solar cell module as a whole.
Therefore, it is necessary to provide a power generating module and light guiding film thereof to solve the aforementioned problems.
The present invention is directed to a light guiding film, which comprises a film base and at least one microstructure. The film base has a first side surface and a second side surface opposite the first side surface. The microstructure is disposed on the first side surface or the second side surface of the film base.
Whereby a plurality of incident light beams become a plurality of output light beams after passing through the light guiding film. An output angle is defined as the angle between the output light beam and the light guiding film. The output angle is defined as 0 degree when the output light beam is downward and parallel with the light guiding film. The output angle is defined as 180 degrees when the output light beam is upward and parallel with the light guiding film. The total luminous flux of the output light beams with the output angles from 70 to 110 degrees is more than 40% of the total luminous flux of the output light beams with the output angles from 0 to 180 degrees.
In the present invention, the light guiding film can guide the incident light beams to emit along a direction perpendicular to the light guiding film. That is, the output light beams are substantially normal to the light guiding film 1.
The present invention is further directed to a power generating module, which comprises a light guiding film and a photoelectric conversion element. The light guiding film is the same as the aforementioned light guiding film. The photoelectric conversion element is disposed adjacent to the first side surface or the second side surface of the film base to receive output light beams from the light guiding film.
The microstructure 12 is disposed on the first side surface 111 or the second side surface 112 of the film base 11. In this embodiment, the microstructure 12 is disposed on the second side surface 112 of the film base 11, wherein the microstructure 12 comprises a first surface 121 and a second surface 122. The second surface 122 is above the first surface 121. A reference plane 20 is defined as a phantom plane that is perpendicular to the first side surface 111 or the second side surface 112 of the film base 11. That is, when the light guiding film 1 stands upright, the reference plane 20 is a phantom horizontal plane. A first inclination angle θ1 is formed between the first surface 121 and the reference plane 20. A second inclination angle θ2 is formed between the second surface 122 and the reference plane 20.
In this embodiment, the value of the first inclination angle θ1 is between 25 to 60 degrees, and the value of the second inclination angle θ2 is between 0 to 15 degrees. The value of the angle between the first surface 121 and the second surface 122 (that is, the sum of the first inclination angle θ1 and the second inclination angle θ2) is between 25 to 75 degrees. Preferably, the value of the first inclination angle θ1 is different from that of the second inclination angle θ2, wherein the first inclination angle θ1 is between 30 to 55 degrees, the second inclination angle θ2 is between 5 to 10 degrees, and the value of the angle between the first surface 121 and the second surface 122 (that is, the sum of the first inclination angle θ1 and the second inclination angle θ2) is between 35 to 65 degrees. In this embodiment, the cross section of the microstructure 12 is substantially triangular, and the first surface 121 intersects the second surface 122. The material of the film base 11 is the same as that of the microstructure 12. They are made of a light transmissible material, such as polymethyl methacrylate (PMMA), arcylic-based polymer, polycarbonate (PC), polyethylene terephthalate (PET), polystyrene (PS) or a copolymer thereof, with a refraction index of 1.35 to 1.65 and a light transmittance between 0.75 to 0.95. It is to be understood that the material of the film base 11 may be different from that of the microstructure 12.
After passing through the light guiding film 1, a plurality of incident light beams 30 become a plurality of output light beams 31 during the actual application of the invention. In this embodiment, the incident light beams 30 are sunlight beams, and the microstructure 12 faces the incident light beams 30. In another embodiment, the microstructure 12 faces away from the incident light beams 30, so the incident light beams 30 illuminate the first side surface 111 of the film base 11 instead.
As shown in
An incident angle θ4 is defined as the angle between the incident light beam 30 and the reference plane 20. The incident angle θ4 is defined as positive when the incident light beam 30 is directed downward, is defined as 0 degrees when the incident light beam (not shown) is horizontal and parallel with the reference plane 20, and is defined as negative when the incident light beam (not shown) is directed upward.
As shown in
In this embodiment, the incident angles θ4 of the incident light beams 30 range from 10 to 80 degrees, and the total luminous flux of the output light beams 31 with output angles ranging from 70 to 110 degrees is more than 40% (preferably, 50%, 60% or 70%) of the total luminous flux of the output light beams 31 with the output angles ranging from 0 to 180 degrees.
The light sources 61, 62, 63, 64, 65, 66, 67 and 68 are used to generate incident light beams at 10, 20, 30, 40, 50, 60, 70, and 80 degrees, respectively. The light sources 61, 62, 63, 64, 65, 66, 67, 68 are turned on at the same time.
Table 1 below shows the testing results of a first type of the light guiding film 1. In the first type of the light guiding film 1, the value of the first inclination angle θ1 is 30 degrees, and the value of the second inclination angle θ2 is 10 degrees. In the Table 1, the ratio of luminous flux (84.23%) of the θt 0°˜180° represents the ratio of the total luminous flux of the output light beams 31 measured by the receivers 69 ranging from 0 to 180 degrees to the total luminous flux provided by the light sources 61, 62, 63, 64, 65, 66, 67, 68. The ratio of energy (77.19%) of the θt 60°˜120° represents the ratio of the total luminous flux of the output light beams 31 measured by the receivers 69 ranging from 60 to 120 degrees to the total luminous flux provided by the light sources 61, 62, 63, 64, 65, 66, 67, 68.
The ratio of luminous flux (63.97%) of the θt 70°˜110° represents the ratio of the total luminous flux of the output light beams 31 measured by the receivers 69 ranging from 70 to 110 degrees to the total luminous flux provided by the light sources 61, 62, 63, 64, 65, 66, 67, 68. The ratio of energy (42.72%) of the θt 80°˜100° represents the ratio of the total luminous flux of the output light beams 31 measured by the receivers 69 ranging from 80 to 100 degrees to the total energy provided by the light sources 61, 62, 63, 64, 65, 66, 67, 68.
The ratio of luminous flux (75.95%) of the θt 70°˜110°/θt 0°˜180° represents the ratio of the luminous flux ratio (63.97%) of the θt 70°˜110° to the luminous flux ratio (84.23%) of the θt 0°˜180°.
As shown in Table 1, because of the specific design of the first inclination angle θ1 (30 degrees) and the second inclination angle θ2 (10 degrees), the ratio of luminous flux of θt 70°˜110°/θt 0°˜180° is 75.95%, which means that 75.95% of the output light beams 31 are directed in the output angles ranging from 70 to 110 degrees. The range of the output angles ranging from 70 to 110 degrees is desired and preferable, because it shows that the light guiding film 1 can guide the incident light beams 30 to emit along a direction perpendicular to the light guiding film 1. That is, the output light beams 31 are substantially normal to the light guiding film 1.
As shown in Table 2, since there is no light guiding film in the comparative example, the comparative example does not have the guiding light's effect. Therefore, only 25.00% of the output light beams 31 exit at the output angles ranging from 70 to 110 degrees.
Table 3 below shows the testing results of a second type of the light guiding film 1. In the second type of the light guiding film 1, the value of the first inclination angle θ1 is 30 degrees, and the value of the second inclination angle θ2 is 5 degrees. The other testing conditions of the second type of the light guiding film 1 are the same as those of the first type of the light guiding film 1.
As shown in Table 3, because of the specific design of the first inclination angle θ1 (30 degrees) and the second inclination angle θ2 (5 degrees), the ratio of luminous flux of θt 70°˜110°/θt 0°˜180° is 83.61%, which means that 83.61% of the output light beams 31 are directed at output angles ranging from 70 to 110 degrees. The range of the output angles ranging from 70 to 110 degrees is desired and preferable, because it shows that the light guiding film 1 can guide the incident light beams 30 to emit along a direction perpendicular to the light guiding film 1. That is, the output light beams 31 are substantially normal to the light guiding film 1.
As shown in Table 4, the ratio of the luminous flux of θt 70°˜110°/θt 0°˜180° is 57.75%, which means that 57.75% of the output light beams 31 are directed at output angles ranging from 70 to 110 degrees. Therefore, most of the output light beams 31 of the third type of the light guiding film 1 are still substantially normal to the light guiding film 1.
Table 5 below shows the testing results of a fourth type of the light guiding film 1. In the fourth type of the light guiding film 1, the value of the first inclination angle θ1 is 55 degrees, and the value of the second inclination angle θ2 is 10 degrees. The other testing conditions of the fourth type of the light guiding film 1 are the same as those of the third type of the light guiding film 1.
As shown in Table 5, the ratio of the luminous flux of θt 70°˜110°/θt 0°˜180° is 58.82%, which means that 58.82% of the output light beams 31 are directed at output angles ranging from 70 to 110 degrees. Therefore, most of the output light beams 31 of the fourth type of the light guiding film 1 are still substantially normal to the light guiding film 1.
While several embodiments of the present invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention should not be limited to the particular forms as illustrated, and that all modifications which maintain the spirit and scope of the present invention are within the scope defined in the appended claims.
Number | Date | Country | Kind |
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102112012 | Apr 2013 | TW | national |