Abstract:
This disclosure provides systems, methods and apparatus including a power generating and a power saving device having a plurality of shutters and a plurality of photovoltaic (PV) devices. In one aspect, each of the plurality of shutters is configured to move laterally in the plane of the shutter by the action of one or more electrostatic actuators. The array of shutters can control the amount of ambient light that is transmitted through the device. Additionally, the array of shutters can shield or expose the array of the PV devices to ambient sunlight to generate PV power.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to the field of photovoltaic power generating devices and more particularly to smart glass panels that can vary the amount of radiation that is transmitted through and generate photovoltaic power. 
       DESCRIPTION OF THE RELATED TECHNOLOGY 
       [0002]    Solar energy is a renewable source of energy that can be converted into other forms of energy such as heat and electricity. Some drawbacks in using solar energy as a reliable source of renewable energy are low efficiency in collecting solar energy, in converting light energy to heat or electricity and the variation in the solar energy depending on the time of the day and the month of the year. 
         [0003]    A photovoltaic (PV) cell can be used to convert solar energy to electrical energy. Systems using PV cells can have conversion efficiencies between 10-20%. PV cells can be made very thin and are not big and bulky as other devices that use solar energy. For example, PV cells can range in width and length from a few millimeters to 10&#39;s of centimeters. Although, the electrical output from an individual PV cell may range from a few milliwatts to a few watts, due to their compact size, several PV cells may be connected electrically and packaged to produce a sufficient amount of electricity. For example, a solar panel including a plurality of PV cells can be used to produce sufficient amount of electricity to satisfy the power needs of a home. 
         [0004]    Solar concentrators can be used to collect and focus solar energy to achieve higher conversion efficiency in PV cells. For example, parabolic mirrors can be used to collect and focus light on PV cells. Other types of lenses and mirrors can also be used to collect and focus light on PV cells. These devices can increase the light collection efficiency. But such systems tend to be bulky and heavy because the lenses and mirrors that are required to efficiently collect and focus sunlight can be large. 
         [0005]    Accordingly, for many applications such as, for example, providing electricity to residential and commercial properties, charging automobile batteries and other navigation instruments, it is desirable that the light collectors and/or concentrators are compact in size. 
         [0006]    PV materials are also increasingly replacing conventional building materials in parts of the building envelope such as windows, roofs, skylight or façades. PV materials incorporated in building envelopes can function as principal or secondary sources of electrical power and help in achieving zero-energy buildings. One of the currently available building-integrated photovoltaic (BIPV) products is a crystalline Si BIPV, which is made of an array of opaque crystalline Si cells sandwiched between two glass panels. Another available BIPV product is a thin film BIPV which is manufactured by blanket depositing PV film on a substrate and laser scribing of the deposited PV film from certain areas to leave some empty spaces and improve transmission. However, such products may suffer from low transmission (5-20%), disruptive appearance and serious artifacts. Additionally, a thin film BIPV may also be expensive to manufacture. 
         [0007]    Accordingly, BIPV systems that can efficiently generate electrical power and reduce manufacturing costs are desirable. 
       SUMMARY 
       [0008]    The systems, methods and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein. 
         [0009]    One innovative aspect of the subject matter described in this disclosure can be implemented in a power generating and power saving device including a transmissive panel, an array of shutters, and an array of PV devices. In some implementations, the transmissive panel has a forward surface for receiving ambient light and a rearward surface opposite the forward surface. The array of shutters is disposed closer to the forward surface of the panel. Each shutter may include a layer of photovoltaic (PV) material disposed facing the forward surface of the panel. Each shutter in the array is adapted to move between an open state and a closed state. The array of PV devices may be disposed rearward of the array of shutters. The array of shutters and the array of photovoltaic devices are structured in shape and/or size such that in the open state a first portion of the received ambient light is transmitted through the rearward surface of the substrate and a second portion of the received ambient light is incident on the layer of PV material on the shutters. The array of shutters and the array of photovoltaic devices are structured in shape and/or size such that in the closed state a first portion of the received ambient light is incident on the layer of PV material on the shutters and a second portion of the received ambient light is incident on the array of PV devices. In various implementations, the array of PV devices can include a thin film photovoltaic cell 
         [0010]    In various implementations, the power generating and power saving device is configured such that in the open state the first portion can be between approximately 30% and approximately 50% of the received ambient light. In some implementations, the device can be configured such that in the open state the second portion can be between approximately 10% and approximately 50% of the received ambient light. In some implementations, in the closed state the first portion can be between approximately 5% and approximately 50% of the received ambient light. In various implementations, in the closed state a second portion can be between approximately 30% and approximately 50% of the received ambient light. In some implementations, in the open state each shutter can be aligned with a corresponding PV device from the array of PV devices such that less than 10% of the received ambient light is directly incident on the array of PV devices. In various implementations, in the closed state each shutter can be offset with respect to a corresponding PV device from the array of PV devices such that the second portion of the received ambient light is directly incident on the PV devices. 
         [0011]    In some implementations of the device, the panel can include a first transmissive substrate having a forward and a rearward surface and the array of shutters can be disposed closer to the rearward surface of the first substrate. In some implementations, the panel can include a second transmissive substrate having a forward and a rearward surface and the array of PV devices is disposed over the forward surface of the second substrate facing the array of shutters. 
         [0012]    In various implementations, some of the array of shutters can include a mechanical shutter that is configured to move laterally in a plane parallel to the forward surface of the panel between the open state and the closed state. The mechanical shutter can be moved between the open state and the closed state by one or more electro-static actuators. The mechanical shutter can be suspended from one or more support structures. In various implementations, the support structure can be configured as a mechanical spring. In some implementations, the support structure can be configured as an electrode of an electro-static actuator that is adapted to slide the mechanical shutter. 
         [0013]    Various implementations of the device can be configured as a window and/or as a skylight. 
         [0014]    Another innovative aspect of the subject matter described in this disclosure can be implemented in a power generating and power saving device including a transmissive panel, a plurality of means for blocking light; and an array of PV devices. The transmissive panel has a forward surface for receiving ambient light and a rearward surface opposite the forward surface. The plurality of means for blocking light is disposed closer to the forward surface of the panel. Each light blocking means includes a layer of photovoltaic (PV) material disposed facing the forward surface of the panel. Each light blocking means is adapted to move between an open state and a closed state. The array of PV devices is disposed rearward of the plurality of light blocking means. The plurality of light blocking means and the array of photovoltaic devices are structured in shape and/or size such that in the open state a first portion of the received ambient light is transmitted through the rearward surface of the panel and a second portion of the received ambient light is incident on the layer of PV material on the light blocking means. The plurality of light blocking means and the array of photovoltaic devices are structured in shape and/or size such that in the closed state a first portion of the received ambient light is transmitted through the rearward surface of the panel and a second portion of the received ambient light is incident on the array of photovoltaic devices. 
         [0015]    In various implementations, the plurality of light blocking means can include a mechanical shutter. In some implementations, the plurality of light blocking means can be configured to move laterally in a plane parallel to the forward surface of the panel between the open state and the closed state. In various implementations, the plurality of light blocking means can be moved between the open state and the closed state by one or more electro-static actuators. 
         [0016]    Another innovative aspect of the subject matter described in this disclosure can be implemented in a method of manufacturing a power generating device. The method includes providing a transmissive panel having a forward surface for receiving ambient light and a rearward surface opposite the forward surface. The method further comprises disposing an array of shutters disposed closer to the forward surface of the panel and disposing an array of PV devices disposed rearward of the array of shutters. Each shutter may includes a layer of PV material that is disposed facing the forward surface of the panel. Each shutter in the array is adapted to move between an open state and a closed state. The array of shutters and the array of PV devices may be are structured in shape and/or size such that in the open state a first portion of the received ambient light is transmitted through the rearward surface of the panel and a second portion of the received ambient light is incident on the layer of PV material on the shutters. The array of shutters and the array of PV devices may be structured in shape and/or size such that in the closed state a first portion of the received ambient light is transmitted through the rearward surface of the panel and a second portion of the received ambient light is incident on the array of PV devices. 
         [0017]    In various implementations, some of the array of shutters can include a mechanical shutter that is configured to move laterally in a plane parallel to the forward surface of the panel between the open state and the closed state. In various implementations, the mechanical shutter can be suspended from one or more support structures. In some implementations, the method further comprises providing an electro-static actuator including the support structure. The electro-static actuator can be adapted to move the mechanical shutter between the open state and the closed state. 
         [0018]    Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Example implementations disclosed herein are illustrated in the accompanying schematic drawings, which are for illustrative purposes only. 
           [0020]      FIGS. 1A and 1B  illustrate an implementation of a panel  100  including an array of shutters, each shutter configured to move laterally in a plane in which the shutter is aligned between an open state and a closed state. 
           [0021]      FIGS. 1C and 1D  illustrate an implementation of a PV power generating panel (for example, the panels depicted in  FIGS. 1A and 1B ) and an array of PV devices. 
           [0022]      FIGS. 2A and 2B  illustrate a plan view of an implementation of an array of microelectromechanical systems (MEMs) based shutters  220  that are electrostatically actuated to move laterally in a plane in which the shutters are aligned between an open state and a closed state. 
           [0023]      FIG. 2C  illustrates a side view of an implementation of a PV power generating panel including the MEMs based shutter depicted in  FIGS. 2A and 2B . 
           [0024]      FIG. 3  is a flow chart  300  illustrating an example of a method of manufacturing an implementation of a power generating device including an array of shutters and PV devices. 
       
    
    
       [0025]    Like reference numbers and designations in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0026]    The following detailed description is directed to certain implementations for the purposes of describing the innovative aspects. However, the teachings herein can be applied in a multitude of different ways. As will be apparent from the following description, the innovative aspects may be implemented in any device or object that is configured to generate PV power, filter solar radiation, and/or control the amount of solar radiation transmitted. More particularly, it is contemplated that the innovative aspects may be implemented in or associated with a variety of applications such as providing power to residential and commercial structures and properties, providing power to electronic devices such as laptops, personal digital assistants (PDA&#39;s), wrist watches, calculators, cell phones, camcorders, still and video cameras, MP3 players, etc. Some of the implementations, described herein can be used in BIPV products such as windows, roofs, skylight or façades. In addition the implementations described herein can be used in wearable power generating clothing, shoes and accessories. Some of the implementations described herein can be used to charge automobile batteries or navigational instruments and to pump water. The implementations described herein can also find use in aerospace and satellite applications. Other uses are also possible. 
         [0027]    As discussed more fully below, various implementations described herein, include a device having an array of light impeding structures (which will be referred to herein as “shutters”) that can be controlled to move between an open state and a closed state to vary the amount of light transmitted. In various implementations, the shutters can include a microelectromechanical systems based device that can be electrostatically actuated to move laterally, for example, move in a plane in which one or more shutters are aligned, between the open state and the closed state. In other implementations, the device includes a fixed array of PV cells which are shielded from or exposed to light when the shutters are moved between an open state and a closed state. In various implementations, some or all the shutters in the array can include PV material on the portion that receives incident light to generate PV power. The amount of light transmitted through the device can be varied between a maximum amount and a minimum amount. The maximum and minimum amount of light transmitted through the device can depend on the size, position, density and shape of the shutters and other structure of the device (for example, apertures). In various implementations, the amount of light transmitted through the device can vary between approximately 0 and 50% of the amount of light incident on the device. 
         [0028]    Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. The implementations described herein can be integrated in architectural structures such as, for example, windows, roof, skylights, or façades to electronically control the amount of incident light that is transmitted and to generate PV power. In such examples, the device functions as mini/micro-blinds that can be electrically controlled and generate PV power. Additionally, various implementations of the device described herein can be used to filter incident UV/IR radiation to prevent heating of the interior of the architectural structures due to radiation. 
         [0029]      FIGS. 1A and 1B  illustrate an implementation of a panel  100  including an array  105  of shutters, each shutter  105   a,    105   b  and  105   c  configured to move laterally in a plane in which the shutter is aligned between an open state and a closed state. The panel  100  illustrated in  FIGS. 1A and 1B  includes a substrate  101  having a forward surface  101   a  that faces the ambient environment and receives ambient light and a rearward surface  101   b  that is opposite the forward surface and through which light exits the panel  100 . A person having ordinary skill in the art will appreciate that the terms “forward” and “rearward” as used in referring to light collector surfaces herein do not indicate a particular absolute orientation, but instead are used to indicate a light collecting surface (“forward surface”) on which natural light is incident and a surface where a portion of the incident light received on the forward surface  101   a  can propagate out from (“rearward surface”). The panel  100  includes a plurality of apertures  106   a,    106   b,  and  106   c  disposed closer to the rearward surface  101   b  of the panel  100  through which ambient light incident on the forward surface  101   a  of the panel  100  is transmitted out of the panel  100 . The transmissivity of the plurality of apertures  106   a - 106   c  can be between approximately 80% and approximately 100%. Portions of the rearward surface  101   b  of the panel  100  (for example, area  125 ) that do not include an aperture can have a transmissivity that varies between approximately 0% and approximately 100%. 
         [0030]    In the open state, the shutters  105   a,    105   b  and  105   c  are in a first position such that they are not aligned with the plurality of apertures  106   a - 106   c.    FIG. 1A  depicts the array  105  of shutters  105   a - 105   c  in the open state. In the open state, the panel  100  is configured to transmit a first portion of the ambient light incident on the forward surface of the panel  100  and block a second portion of the ambient light incident on the exterior portion of the panel  100 . For example, as illustrated in  FIG. 1A , a first radiation beam  120  (for example, light) that enters the panel  100  and is not incident on any of the shutters  105   a,    105   b  and  105   c  in the array  105  is transmitted through the aperture  106   b  out of the rearward surface  101   b  of the panel  100 . In the same configuration a portion of the ambient light, for example, a second radiation beam  115  (for example, light) that enters the panel  100  and is incident on any of the shutters  105   a,    105   b  and  105   c  in the array  105  is blocked by the shutters  105   a - 105   c  and is not transmitted through the panel  100 . Accordingly, the panel  100  has a transmissivity less than 100% in the open state. In various implementations, the transmissivity of the panel  100  can vary between approximately 30% and approximately 50% depending on the size, shape and density of the shutters  105   a - 105   c  and the apertures  106   a - 106   c.    
         [0031]    The amount of light transmitted through the panel  100  can be varied by moving the shutters  105   a,    105   b  and  105   c  to a closed state.  FIG. 1B  depicts the array  105  of shutters  105   a - 105   c  in the closed state. In the closed state, the shutters  105   a,    105   b  and  105   c  are moved laterally in a plane in which the shutters  105   a - 105   c  are aligned (for example, to the left) to a second position such that each shutter  105   a - 105   c  is aligned with a corresponding aperture  106   a - 106   c.  In various implementations, the plane in which the shutters  105   a - 105   c  are aligned can be parallel to the plane of the forward surface  101   a  or the rearward surface  101   b  or both. In the closed state, the first radiation beam  120  which was previously transmitted through the panel  100  is now incident on the shutter  105   b  and blocked from exiting through aperture  106   b  and the second radiation beam  115  which was previously incident on the shutter  105   a  is now incident on the area  125  of the rearward surface  101   b  of the panel  100  that does not include an aperture. Depending on the transmissivity of the area  125 , the optical beam  115  can be blocked or partially/completely transmitted through the panel  100 . In some implementations the shutters  105  can be configured to move between a “shut” and a full open position. In other implementations, the shutters  105  are configured to be positioned at one or more positions between a maximum open position and a minimum open position. Depending on the size, shape and density of the shutters  105   a - 105   c  and the apertures  106   a - 106   c  and the transmissivity of the portion of the rearward surface of the panel  100  that is devoid of apertures, the panel  100  has a transmissivity that can vary between approximately 0% and approximately 50% in the closed state. 
         [0032]    In the implementations illustrated in  FIGS. 1A and 1B , only the amount of light that is transmitted through the panel  100  is regulated. If the panel  100  illustrated in  FIGS. 1A and 1B  are configured for use as a window or a skylight, then the shutters  105   a - 105   c  function as mini/micro blinds that are integrated in the window or the skylight. Depending on the design of the shutters  105   a - 105   c,  the amount of light that is transmitted through the panel  100  can be controlled electrically. 
         [0033]    In various implementations, the light that is blocked by the shutters  105   a - 105   c  can be used to generate PV power.  FIGS. 1C and 1D  illustrate an implementation of a PV power generating panel  150  including the panel  100  depicted in  FIGS. 1A and 1B  and an array  110  of PV devices  110   a,    110   b  and  110   c.  In various implementations, the array  110  of PV devices  110   a - 110   c  may be disposed closer to the rearward surface  101   b  of the panel  150 . For example, the array  110  of PV devices  110   a - 110   c  can be disposed on the portion (for example, area  125 ) of the rearward surface of the panel  150  that does not include an aperture. In the implementation illustrated in  FIGS. 1C and 1D , the array  105  of shutters  105   a - 105   c  is disposed closer to the forward surface of the PV power generating panel  150  and the array  110  including PV devices  110   a,    110   b  and  110   c  is disposed rearward of the array of shutters  105  closer to the rearward surface of the panel  150 . In some implementations, each shutter  105   a - 105   c  can include a PV device  130  that can absorb ambient light and generate PV power. 
         [0034]      FIG. 1C  depicts the PV power generating panel  150  in the open state. In this configuration, the shutters  105   a - 105   c  are in a first position and are aligned with the array of PV devices  110   a,    110   b  and  110   c  such that each shutter  105   a,    105   b  and  105   c  in the array  105  overlaps partially or completely with a corresponding PV device  110   a,    110   b  and  110   c  in the array  110  as illustrated in  FIG. 1C . In this configuration, as described above with reference to  FIG. 1A , the first radiation beam  120  enters the panel  150  and is not incident on any of the shutters  105   a,    105   b  and  105   c  in the array  105 , and propagates through the propagates through the interior portion of the panel  150  and passes out through aperture  106   b.  In the same configuration the portion of the ambient light represented by the second radiation beam  115  that was previously blocked by the shutter  105   a  and is now absorbed by the PV device  130  included in the shutter  105   a  and converted to electrical power. 
         [0035]      FIG. 1D  depicts the PV power generating panel  150  in the closed state. In this configuration, each of the shutters  105   a - 105   c  is moved laterally in a plane in which the shutter is aligned (for example, to the left) to a second position such that each shutter  105   a - 105   c  is aligned with a corresponding aperture  106   a - 106   c.  In other words, each shutter  105   a - 105   c  may be aligned with an aperture  106   a - 106   c  with respect to the direction of radiation (e.g., radiation beams  115  and  120 ) propagated through the panel  150 . In various implementations, in the second position, each shutter  105   a - 105   c  may not overlap with a corresponding PV device  110   a,    110   b  and  110   c  in the array  110  as illustrated in  FIG. 1D . In other implementations, in the second position, each shutter  105   a - 105   c  may overlap with a corresponding PV device  110   a,    110   b  and  110   c  in the array  110  to a lesser extent as compared to the extent of overlap in the first position. In the closed state, the optical beam  120  which was previously transmitted through the panel  150  is now absorbed by the PV device  130  included in the shutter  105   b  and converted to PV power. The second radiation beam  115  which was previously incident on the shutter  105   a  is now incident on the PV device  110   a  of the array  110  and converted to PV power. 
         [0036]    In accordance with the discussion above, the amount of light transmitted through the panel  150  is reduced in the closed state as compared to the amount of light transmitted through the panel in the open state. In the closed state, or a partially closed state, more incident radiation reaches PV device  110 . Consequently, in the closed state, the amount of power generated is increased as compared to the amount of PV power generated in the open state. In various implementations, the transmissivity of the panel  150  in the open state can vary between approximately 30% and approximately 50% depending on the size, shape and density of the shutters  105   a - 105   c,  the apertures  106   a - 106   c,  and the PV devices  110   a - 110   c.  Depending on the size, shape and density of the shutters  105   a - 105   c,  the apertures  106   a - 106   c  and the PV devices  110   a - 110   c,  the panel  150  has a transmissivity that can vary between approximately 0% and approximately 50% in the closed state. 
         [0037]    The substrate  101  includes a transparent or transmissive material such as glass, plastic, polycarbonate, polyester or cyclo-olefin. In various implementations, the forward and rearward surfaces  101   a  and  101   b  of the substrate  101  can be parallel. In other implementations, the substrate  101  can be wedge shaped such that the forward and rearward surfaces  101   a  and  101   b  are inclined with respect to each other. The substrate  101  may be formed as a plate, sheet or film, and fabricated from a rigid or a semi-rigid material. In various implementations, portions of the substrate  101  may be formed from a flexible material. In some implementations, the panel  150  can include two transmissive substrates. A first transmissive substrate can include the shutters  105   a - 105   c  and a second substrate disposed rearward of the first substrate can include the PV devices  110   a - 110   c.  In various implementations, the two substrates may be separated by a gap. In various implementations, the substrate  101  can have a thickness such that the panels  100  and  150  have a thickness of about 0.5-8 inches. 
         [0038]    The PV devices  110   a - 110   c  and  130  can convert radiation into electrical power. In various implementations, the PV devices  110   a - 110   c  and  130  can include solar cells. The PV devices  110   a - 110   c  and  130  can include a single or a multiple layer p-n junction and may be formed of silicon, amorphous silicon or other semiconductor materials such as cadmium telluride. In some implementations, PV devices  110   a - 110   c  and  130  can include photo-electrochemical cells. Polymer or nanotechnology may be used to fabricate the PV devices  110   a - 110   c  and  130 . In various implementations, PV devices  110   a - 110   c  and  130  can include thin film photodiodes having several multispectrum layers, each multispectrum layer can have a thickness between approximately 1 μm to approximately 250 μm. The multispectrum layers can further include nanocrystals dispersed in polymers. Several multispectrum layers can be stacked to increase efficiency of the PV devices  110   a - 110   c  and  130 . 
         [0039]    In various implementations, the shutters  105   a - 105   c  can include mechanical shutters that reflect or absorb ambient light. The mechanical shutters can be slidable laterally in the plane in which the shutters aligned or rotatable about an axis intersecting the shutter. For example, the shutters  105   a - 105   c  can include deformable mirror device (DMDs) which are rotatable or pivotable about an axis. An example of a slidable opto-mechanical shutter is described below with reference to  FIGS. 2A-2C . The opto-mechanical shutters can be actuated (for example, moved horizontally, vertically, diagonally or rotated about an axis) by using electrostatic effect, piezo-electric effect, or mechanically. Although, the  FIGS. 1A-1D  show an opto-mechanical shutter, in various implementations, the shutters  105   a - 105   c  can utilize opto-electric, acousto-optic, interference or diffraction phenomenon to vary the transmissivity of ambient light. In some implementations the shutters  105   a - 105   c  can include liquid crystal material that can vary between a transmissive state and an absorptive/reflective state to vary the transmissivity of ambient light. Other shutters that are known to a person having ordinary skill in the in the art can also be used. Although  FIGS. 1A-1D  depict that all the shutters  105   a - 105   c  are simultaneously open or simultaneously closed, a person having ordinary skill in the art would realize that in some implementations each shutter  105   a - 105   c  can be individually controlled such that only some of the shutters is open while the rest are closed. This can be useful to further control the amount of light transmitted through the panel  100  and  150  and the amount of PV power generated by the panel  150 . Additionally, although  FIGS. 1A-1D  and the description above disclose that the shutters  105   a - 105   c  are moved between a first position and a second position. A person having ordinary skill in the art would recognize that in various implementations, the position of the shutters  105   a,    105   b  and  105   c  can be varied between the open state and the closed state such that the shutters  105   a - 105   c  occupy a variety of positions (for example, one or more positions) between the first and the second position. In such implementations, the amount of light transmitted through the panels  100  and  150  can be varied continuously, semi-continuously or discretely between a maximum amount and a minimum amount. 
         [0040]      FIGS. 2A and 2B  illustrate a plan view of an implementation of an array of microelectromechanical systems (MEMs) based shutters  220  that are electrostatically actuated to move laterally in a plane in which the shutters are aligned between an open state and a closed state. Each of the MEMs based shutter  220  depicted in  FIGS. 2A and 2B  can be individually driven by a pair electrostatic actuators to block and unblock light. One electrostatic actuator from the pair of electrostatic actuators is configured to close the shutter and another is configured to open the shutter. Each shutter  220  is suspended from support beam  230  which is anchored at a support beam anchor  225 . In some implementations the support beam  230  acts as a mechanical spring and also as a first electrode of one of the actuators. A drive beam  215  anchored at a drive beam anchor  210  may act as a second electrode of one of the actuators. An electrical connection for activating the shutters may be provided through the drive beam anchor  210 . In this implementation, the shutter  220  may be actuated by applying a potential difference between the support beam  230  (first electrode) and the drive beam  215  (second electrode). The applied potential difference generates an attractive force which pulls the support beam  230  toward the drive beam  215  resulting in the shutter  220  being pulled laterally.  FIG. 2A  depicts the array of MEMs based shutters  220  in the open state and  FIG. 2B  depicts the array of MEMs based shutters  220  in the closed state. 
         [0041]      FIG. 2C  illustrates a side view of an implementation of a PV power generating panel  150  including the MEMs based shutter  220  depicted in  FIGS. 2A and 2B . The panel  150  illustrated in  FIG. 2B  includes a first transmissive substrate  205   a  including the array of shutters  220  and a second transmissive substrate  205   b  including the apertures  106   a - 106   c  and the PV devices  110   a - 110   c.  The first and the second transmissive substrates  205   a  and  205   b  are separated by a spacer  245 . In various implementations, the shutter  220  can include the PV device  130  discussed above. In the PV power generating panel  150 , the array of shutters  220  is disposed closer to the rearward surface of the first substrate  205   a  and the array of PV devices  110   a - 110   c  is disposed closer to (or on the) forward surface of the second substrate  205   b.  The array of shutters  220  can be fabricated on the rearward surface of the substrate  205   a  by using a variety of fabrication methods such as patterning, etching, lithography, chemical and physical vapor deposition techniques, etc. The array of PV devices  110   a - 110   c  can be fabricated on the forward surface of the substrate  205   b  by using a variety of fabrication methods such as patterning, etching, lithography, chemical and physical vapor deposition techniques, etc. 
         [0042]      FIG. 3  is a flow chart  300  illustrating an example of a method of manufacturing an implementation of a power generating device including an array of shutters and PV devices. The method includes providing a transmissive panel as shown in block  305 . The transmissive substrate can be similar to the substrates  101 ,  205   a  and  205   b  discussed above. The method further includes disposing an array of shutters closer to a forward surface of the panel as shown in block  310 . The array of shutters can be similar to the shutters  105   a - 105   c  and  220  discussed above. The method also includes disposing an array of PV devices rearward of the array of shutters as shown in block  315 . The array of shutters and the PV devices can be disposed using a variety of fabrication methods known to a person having ordinary skill in the art including but not limited to patterning, etching, lithography, chemical and physical vapor deposition techniques, etc. 
         [0043]    The implementations described herein can include filters to reduce the amount of ultraviolet (UV) or infrared (IR) radiation that is transmitted through. The implementations described herein can additionally be configured to reduce color dispersion and image distortion; serve as thermal barrier and block solar radiation thereby aid in reducing heating and cooling costs; be designed to meet advanced building codes and standards; minimize fire hazard; supply better daylight as compared to conventional BIPV products; recycle indoor lighting energy; help in achieving “net zero building” by generating electric power, be cut into arbitrary shapes and sizes according to the building requirement and be aesthetically pleasing as conventional windows. 
         [0044]    A wide variety of other variations are also possible. Films, layers, components, and/or elements may be added, removed, or rearranged. Additionally, processing operations may be added, removed, or reordered. Also, although the terms film and layer have been used herein, such terms as used herein include film stacks and multilayers. Such film stacks and multilayers may be adhered to other structures using adhesive or may be formed on other structures using deposition or in other manners. 
         [0045]    Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Additionally, a person having ordinary skill in the art will readily appreciate, the terms “upper” and “lower” are sometimes used for ease of describing the figures, and indicate relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the proper orientation of the device as implemented. 
         [0046]    Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. 
         [0047]    Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.