Abstract:
The present invention proposes a posture-adjustable solar-collecting window blind, which can adjust the position of solar cells to better collect solar energy. In the window blind, a solar detector and an ampere meter are used to detect the relationship between the incident angle of sunlight and an optimal arrangement of the solar detector. The relationship can be further used to adjust the positions of the plurality of solar cells. Furthermore, the window blind comprises a light sensor to detect the light intensity of a target area, which can be complementarily used to adjust the position of the plurality of solar cells.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to window blinds capable of collecting solar energy, in particular window blinds comprising posture-adjustable solar panels. 
       BACKGROUND OF THE INVENTION 
       [0002]    Windows are an important part of our houses. One of their main functions is to allow sunlight to pass into the inside of houses or block the entrance of sunlight. Recently ideas have been developed for installing solar panels in windows to collect solar energy and convert it into electricity. Among them, SHARP&#39;s LumiWall product combines solar power generation, daylight transmission and illumination. In a LumiWall product, a number of thin-film solar panels are embedded inside the glass to convert solar energy into electricity during daytime hours, and provide illumination as white-LED during nighttime. A LumiWall product will not really generate much electricity for use in house; its aim is to create an aesthetically-pleasing, self-contained illumination device. 
         [0003]    However, among all the available solutions, there is no solution for window installation, especially window blinds, such that autonomous optimization of the shape/position/posture takes place for best solar energy collection and conversion. 
       SUMMARY OF THE INVENTION 
       [0004]    It is a first object, according to embodiments of the present invention, to propose a posture-adjustable window blind for improving the solar-collection efficiency, especially adjusting postures of solar cells mounted on the window blind, depending on the incidence angle of sunlight. 
         [0005]    According to an embodiment of the present invention, a window blind is proposed that comprises a solar detector, an ampere meter, a plurality of solar cells and a motor. In said embodiment, the solar detector is configured to collect solar energy, the ampere meter is configured to measure the output current of the solar detector to find an optimal arrangement of the solar detector corresponding to the maximum output current or an expected output current, each of the plurality of solar cells is configured to be mounted on a corresponding slat of the window blind and collect solar energy and convert it into electricity, and the motor is configured to adjust the postures, especially the tilt angles, of the plurality of solar cells, based on the optimal arrangement of the solar detector. 
         [0006]    In this proposed window blind, the solar detector and the ampere meter can be used to determine the relationship between the arrangement of the solar detector, the incidence angle of the sunlight and the conversion efficiency of the solar energy. The arrangement of the solar detector can be its shape, tilt angle, position, or posture. Furthermore, the relationship can be used to adjust the postures of the solar cells to maximize the collection of solar energy or to collect solar energy on demand. 
         [0007]    Preferably, the solar detector can be located at a substantially central area of the region formed by the plurality of solar cells, for providing closer information, for example on the influence of the incidence angle of sunlight on solar energy collection, for better adjusting the posture of the plurality of solar cells. 
         [0008]    Preferably, the solar detector can be in the shape of a wheel and comprise a plurality of sub-solar-detectors. The ampere meter is further configured to measure the individual output current of each sub-solar-detector, so as to find the specific sub-solar-detector generating the maximum output current or an expected output current. The posture of the specific sub-solar-detector can be used to represent the arrangement of the solar detector. 
         [0009]    Optionally, the solar detector can be a simple solar panel and its tilt posture can be adjusted by a second motor. By adjusting the tilt angle of the solar detector and measuring the output current at different tilt angles, the tilt angle of the solar detector can be directly used to determine the favorable tilt angle of the plurality of solar cells. 
         [0010]    Optionally, the window blind can further comprise a memory to record the relationship between time and the optimal arrangement of the solar detector. The recorded relationship is helpful to adjust the posture of the plurality of solar cells. 
         [0011]    It is another object, according to an embodiment of the present invention, to make the window blind provide illumination based on a predefined profile, the latter defining the relationship between time and an expected light intensity of a predefined area. 
         [0012]    Optionally, the window blind can further comprise a light sensor, which is configured to measure the light intensity of the predefined area, and a second memory, which is configured to store the predefined profile. The motor is further configured to adjust the tilt angle of the plurality of solar cells, based on the output of the light sensor and the pre-defined profile. 
         [0013]    Optionally, the window blind can further comprise an energy storage for storing the converted electricity. The energy storage can be arranged so as to be distributed in one or more slats, which means that the obtained energy is locally stored inside one or more slats. The energy storage can also take place in a centralized way, physically independent of the window blind. The stored electricity can be provided to a light source to illuminate the predefined area or to any appliance in the house. 
         [0014]    These and other aspects, features, and/or advantages of the present invention will be apparent from and elucidated with reference to the embodiments described hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    For a more complete understanding of the present invention, and the advantages thereof, the following descriptions refer to the accompanying drawings, in which: 
           [0016]      FIG. 1  illustrates a schematic window blind, according to embodiments of the present invention; 
           [0017]      FIG. 2  illustrates an exemplary solar detector and ampere meter according to an embodiment of the present invention; 
           [0018]      FIG. 3  illustrates an exemplary solar detector and ampere meter according to an embodiment of the present invention; 
           [0019]      FIG. 4  illustrates a figure representing the relationships between the tilt angle of the plurality of solar cells and the time, according to embodiments of the invention. 
       
    
    
       [0020]    Throughout the drawings, same or similar reference numerals will be understood to represent the same or similar modules, functions or features. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0021]    In the following description,  FIG. 1  is used to illustrate several window blinds according to several embodiments of the present invention, and different modules will be described in detail accompanying with different embodiments. Incorporating all modules in one figure is just for the simplicity of the description, and should not be understood that each module in  FIG. 1  is essential for the present invention. 
         [0022]    In the first embodiment shown in  FIG. 1 , a window blind  100  comprises a plurality of slats  110 ,  120 , and  130  and a plurality of solar cells  112 ,  122 , and  132 . Each solar cell is configured to collect solar energy and convert it into electricity. Each solar cell can be mounted on a corresponding slat, and the mount can be rigid, which means that the movements of the slat and the solar cell are synchronous, or the mount can be flexible, which means that the movements of the slat and the solar cell can be asynchronous. In the latter situation, the posture of each solar cell can be adjusted independent of the posture of the corresponding slat. Each solar cell can be a solar panel with different size. For example, each solar cell may have a comparative size as that of the slat it is mounted on, or several solar cells may be mounted on one slat. Also, it is not necessary for each slat to have a solar cell mounted on it. The window blind  100  further comprises a solar detector  150 , which is configured to collect solar energy and convert it into electricity. The solar detector  150  can be a solar panel independent of the plurality of solar cells  112 ,  122 , and  132 . The size and shape of the solar detector  150  can be different from a single solar cell  112 ,  122 , and  132 , or it may have the same or similar size and shape as a single solar cell  112 ,  122 , or  132 . However, for the benefit of ease-of-description, we can virtually separate the solar detector  150  from the plurality of solar cells  112 ,  122 , and  132 , in this case. An ampere meter  160  is provided to measure the output current of the solar detector  150  to find an optimal arrangement of the solar detector  150  corresponding to the maximum output current or an expected output current. In this embodiment, the ampere meter  160  measures the output current from the solar detector. If in some cases, there are some circuits/modules that convert the output current to, and present it in the form of, a voltage, a voltage meter is also applicable for the present invention. The solar detector  150  and the ampere meter  160  together determine the optimal arrangement of the solar detector  150  responding to the incidence angle of sunlight. The arrangements of the solar detector  150  can include the posture, shape, or any other measurement to describe the arrangement of the solar detector  150 . The window blind  100  further provides a motor  170  to adjust the posture, e.g., tilt angle, of the plurality of solar cells, based on the optimal arrangement of the solar detector  150 . If each solar cell  112 ,  122 ,  132  is rigidly mounted on a corresponding slat  110 ,  120 ,  130 , the motor can adjust the posture, i.e., tilt angle, of each slat to further adjust the posture of each solar cell. If each solar cell  112 ,  122 ,  132  is flexibly mounted on a corresponding slat  110 ,  120 , and  130 , the motor can directly adjust the posture of each solar cell or adjust both the slats and the solar cells. 
         [0023]    By measuring the output current of the solar detector  150 , based on its different arrangements, an optimal arrangement corresponding to the maximum output current or an expected output current can be determined The optimal arrangement can be further used to determine the arrangement, e.g., tilt angle, of the plurality of solar cells, which may further provide a maximum current or a second expected current. This function is performed autonomously, without the intervention by operators. 
         [0024]    The solar detector  150  may be placed at different postures. In an embodiment, the solar detector  150  is placed at a substantially central area of the region formed by the plurality of solar cells, which may closely reflect the influence of the incidence angle of sunlight on the solar-to-electricity conversion of the plurality of solar cells. In other embodiments, the solar detector  150  may be placed at an edge of the window blind, which is advantageous for installation. 
         [0025]    No matter where and how the solar detector  150  is mounted, the ampere meter  160  may be closely coupled to the solar detector  150 , which provides the benefit of a compact module, or loosely coupled to the solar detector  150 , e.g., by electrical wire, which provides the benefit of convenient installation. 
         [0026]      FIG. 2  illustrates an exemplary embodiment of the solar detector  150 ′ according to an embodiment of the invention. The solar detector  150 ′ is formed in the shape of a wheel and comprises a plurality of sub-solar-detectors  152 ,  154 , and  156 , wherein each sub-solar-detector is capable of collecting solar energy and converting it into electricity independently. The ampere meter  160 ′ is further configured to measure the output current of each sub-solar-detector so as to find a specific sub-solar-detector generating the maximum output current or an expected output current. The arrangement, e.g., posture or index, of the specific sub-solar-detector  152 ,  154 , or  156 , can be used to represent the arrangement of the solar detector  150 ′. A skilled person should understand that, in all embodiments of the present invention, the optimal arrangement of the solar detector should not be limited to the posture corresponding to the maximum output current, but also can be a posture corresponding to an expected output current. The first case is for collecting maximum energy, while the latter case may be for generating the demanded current depending on specific applications. 
         [0027]    Alternatively,  FIG. 3  illustrates an exemplary embodiment of the solar detector  150 ″, which can be a flat solar panel and its tilt angle can be adjusted by a second motor  310 . By adjusting the tilt angle of the solar detector  150 ″, the output current measured by the ampere meter  160 ″ can be changed. Subsequently, the optimal arrangement of the solar detector  150 ″ can be determined. 
         [0028]    As known, there is some inherent relationship between the time and the incident angle of sunlight. And the inventors found that there are different kinds of relationships between the time and the favorable arrangement of the solar detector. The latter can be influenced by the incident angle of sunlight. 
         [0029]    Optionally, the relationship between time and arrangement of the solar detector  150  can be stored in a memory  180 , which is illustrated in  FIG. 4 . For example, the arrangement of the solar detector  150  can be its tilt angle or the index/posture of the specific sub-solar-detector. In the embodiment of  FIG. 4 , the X axis represents the time, and the Y axis represents the tilt angle of the solar detector. Each curve is basically a plot of the optimal arrangement of the solar detector during the day. Due to the revolution of the Earth around the Sun, the incident angle of sunlight may even be different at the same time of a different day. Therefore it is practical for the memory  180  to store several curves, each curve representing a specific season or month. For example, curve  410  represents the spring, curve  420  represents the summer, while curve  430  represents the winter. 
         [0030]    The motor  170  in an embodiment of  FIG. 1  can be further configured to adjust the tilt angle of the plurality of solar cells, by taking into account the current time and the relationship stored in the memory  180 . 
         [0031]    One main function of a window blind is letting the sunlight pass through and illuminate a predefined area. It is another object, according to an embodiment of the present invention, to make the window blind provide illumination based on a predefined profile, the latter defining the relationship between time and an expected light intensity of a predefined area. To reach this object, the window blind  100 , in an embodiment illustrated in  FIG. 1 , can further comprise a light sensor  190 , configured to measure the light intensity of a predefined area, and a second memory  192 , configured to store a pre-defined profile that defines the relationship between time and a desired light intensity of the predefined area. The motor  170  is further configured to adjust the tilt angle of the plurality of solar cells based on the output of the light sensor  190  and the pre-defined relationship stored in the second memory  192 . For example, the user wants the predefined area to have a higher light intensity at a specific time: while the light sensor  190  detects that the current light intensity is lower than expected, the motor  170  may adjust the tilt angle of the plurality of solar cells  112 ,  122 , and  132  to collect and convert more solar energy into electricity and provide it to a light source to compensate the insufficient light intensity. The light source may be an independent lamp in the room or a plurality of LEDs coupled to the window blind, compensating the light intensity passing through the window blind. In the latter scenario, each slat may be, or comprise, a transparent and light-conductive material, for example, a light guide plate made of PMMA (Polymethyl Methacrylate). 
         [0032]    If the light sensor  190  detects that the light intensity is higher than expected, the motor  170  may adjust the tilt angle of the plurality of solar cells to reduce the converted solar energy, which may reduce the output light intensity of the light source or even power off the light source. 
         [0033]    To store the converted electricity, the window blind may further comprise an energy storage. The stored energy can be supplied to the light source or any other appliances. Also, the stored energy can be supplied to the mains grid, where it can be used in the same way as the electricity generated and transmitted by the electricity grid. 
         [0034]    Those skilled in the art would appreciate that various modifications are possible in the method and apparatus thereof provided in various embodiments of the invention without departing the spirit or scope of the invention. Therefore, the scope of the invention should be construed by the appended claims. 
         [0035]    The remarks made hereinbefore demonstrate that the detailed descriptions with reference to the drawings illustrate rather than limit the invention. There are numerous alternatives, which fall within the scope of the appended claims. Any reference sign in a claim should not be construed as limiting the claim. The word “comprising” does not exclude the presence of other elements or steps than those listed in a claim. The word “a” or “an” preceding an element or step does not exclude the presence of a plurality of such elements or steps.