Abstract:
An illumination system comprises a main waveguide, a scattering structure, and an extending waveguide. The main waveguide includes an incident face and a surface opposite the incident face, wherein external light passes through the incident face into the main waveguide. The scattering structure is disposed on or close to the surface of the main waveguide so as to scatter the external light transmitted into the main waveguide. 
     The extending waveguide has an illuminating surface and a joint interface between itself and the main waveguide. The joint interface is not shaded by the scattering structure and allows the scattered external light to pass through the illuminating surface to illuminate an illuminated area. According to an embodiment of the present invention, the illumination system is simple and efficiently collecting the external light in a broader incident angle to provide illumination. A method for manufacturing the illumination system is also disclosed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an illumination system and a manufacturing method thereof, particularly to an illumination system able to transmit solar light and a manufacturing method thereof. 
         [0003]    2. Description of the Prior Art 
         [0004]    The conventional solar tracking system collects and guides solar light for green energy illumination or solar power generation. Normally, it required a bulky support system and an optical mirror structure; hence the installation was usually limited by the space and location. The concentration ratio of the tracking system could be significantly influenced by the incident angle of solar light. Therefore, in order to capture solar light precisely, a direction control system is needed. However, such direction control system is expensive and inconvenient to operate. Besides, a direction control system may impair the light concentration effect of a solar tracking system. 
         [0005]    Accordingly, how to capture solar light in a broad angle simply and efficiently has become a problem the researchers and manufacturers are eager to overcome. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides an illumination system and a manufacturing method thereof, which uses a soft waveguide material featuring flexibility, plasticity and wide-angle light capturing capability to conduct solar light for illumination. The soft waveguide material has superior weathering resistance and can be used to encapsulate and protect various electronic elements and modules. Therefore, the soft waveguide material can be used in various locations. Besides, the soft waveguide material is made of a high light transmission polymer or an organic polymer, which is environment-friendly, biocompatible and suitable for green energy application. 
         [0007]    In one embodiment, the illumination system of the present invention comprises a main waveguide, a scattering structure and an extending waveguide. The main waveguide includes an incident face and a surface opposite the incident face, wherein external light passes the incident face into the main waveguide. The scattering structure is disposed on or close to the surface of the main waveguide so as to scatter the external light transmitted into the main waveguide. The extending waveguide has an illuminating surface and a joint interface between itself and the main waveguide. The joint interface is not shaded by the scattering structure and allows the scattered light to pass through the illuminating surface to illuminate an illuminated area. 
         [0008]    In one embodiment, the method for manufacturing an illumination system of the present invention comprises steps: providing an extending waveguide having an illumination surface; placing a portion of the extending waveguide in a mold; filling a waveguide material in the mold and curing the waveguide material to form a main waveguide joined with the extending waveguide, wherein the main waveguide includes an incident face and a surface opposite the incident face and a scattering structure disposed on or close to the surface, and wherein the scattering structure does not shade a joint interface between the extending waveguide and the main waveguide. 
         [0009]    Below, embodiments are described in detail in cooperation with the attached drawings to make easily understood the objectives, technical contents, characteristics and accomplishments of the present invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1 a    is a diagram schematically showing an illumination system according to one embodiment of the present invention; 
           [0011]      FIG. 1 b    is a diagram schematically showing an illumination system according to another embodiment of the present invention; 
           [0012]      FIG. 2  is a diagram schematically showing an illumination system according to yet another embodiment of the present invention; 
           [0013]      FIG. 3  is a diagram schematically showing an illumination system according to still another embodiment of the present invention; 
           [0014]      FIG. 4  is a diagram showing a current-voltage relationship of an illumination system under an external light source according to one embodiment of the present invention; and 
           [0015]      FIG. 5  is a diagram showing a current-voltage relationship of an illumination system under another external light source according to one embodiment of the present invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    Below, embodiments of the present invention will be described in detail in cooperation with drawings. In addition to the embodiments described in the specification, the present invention also widely applies to other embodiments. Any substitute, modification or variation that can be easily completed according to the spirit of the present invention is to be included within the scope of the present invention, which is based on the claims of the present invention. Many special details are provided in the specification to enable the readers to comprehend the present invention. However, the present invention can still be practiced without a portion of or all the special details. Besides, the elements or steps, which are well known by the persons skilled in the art, are not described in the details lest they become unnecessary limitations on the present invention. Identical or similar elements will be denoted with identical or similar symbols in the drawings. It should be noted: the drawings do not present the actual sizes or numbers of the elements but only schematically show the present invention; some details may not be depicted in the drawings lest the conciseness of the drawings be impaired. 
         [0017]    Refer to  FIG. 1  a an illumination system according to one embodiment of the present invention. The illumination system of the present invention comprises a main waveguide  10 , a scattering structure  13 , and an extending waveguide  20 . The main waveguide  10  includes an incident face  11  and a surface  12  opposite the incident face  11 . In the embodiment shown in  FIG. 1 a   , the incident face  11  is a protrudent semispherical surface. However, the present invention does not limit that the incident face  11  must be a protrudent semispherical surface. In one embodiment, the incident face  11  is extended to the surface  12  to form a semispherical main waveguide. In other embodiments, the incident face  11  is a plane or a concaved surface. The present invention does not particularly limit the shape of the main waveguide  10 . The persons skilled in the art should be able to make appropriate modification or variation without departing from the spirit of the present invention. The scattering structure  13  is disposed on the surface  12  of the main waveguide  12  or embedded in the interior of the main waveguide  10 , which are near the surface  12 . For convenience, “disposed on the surface  12  or embedded in the interior of the main waveguide  10 , which are near the surface  12 ” is stated as “disposed on or close to the surface  12  ” thereinafter. In other words, the scattering structure  13  is disposed on or close to the surface  12  of the main waveguide  10 . 
         [0018]    In the embodiment shown in  FIG. 1 a   , the extending waveguide  20  has an illuminating surface  12  and is joined with the main waveguide  10 . The extending waveguide  20  penetrates the scattering structure  13 . Therefore, the scattering structure does not shade a joint interface  22  between the main waveguide  10  and the extending waveguide  20 . Refer to  FIG. 1 b    for another embodiment. In the embodiment shown in  FIG. 1 b   , the extending waveguide  20  has an illuminating surface  21  and is joined with a side surface  14  of the main waveguide  10 , wherein the side surface  14  is connected with at least one of the incident face  11  and the surface  12  of the main waveguide  10 . In the embodiment shown in  FIG. 1 b   , the scattering structure  13  does not shade the joint interface  22  between the main waveguide  10  and the extending waveguide  20 . 
         [0019]    While external light L passes the incident face  11  into the main waveguide  10 , the external light L is scattered by the scattering structure  13 . The scattered external light L enters the extending waveguide  20  and passes through the illuminating surface  21  to illuminate an illuminated area. 
         [0020]    The main waveguide  10  is made of at least one of thermoplastic elastomer (TPE) and photocurable polymer (PCP). TPE is a high-resilience, environmental-protection, non-toxic and safe material. TPE is softer and more elastic than plastic material. The fabrication of TPE products is exempted from vulcanization. TPE has superior coloring capability and weathering resistance. The TPE waveguide materials include thermoplastic rubber (TPR), thermoplastic vulcanizate (TPV), thermoplastic polyurethane (TPP), and thermoplastic polyether ester elastomer (TPEE). The PCP waveguide material includes polydimethylsiloxane (PDMS). The usually used flexible waveguide materials are listed in Table.1. 
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Material (Abbreviation) 
                 Classification 
               
               
                   
                   
               
             
             
               
                   
                 Polystyrene (PS) 
                 TPR 
               
               
                   
                 Styrene-Ethylene/Butylene-Styrene 
                 TPR 
               
               
                   
                 (SEBS) 
               
               
                   
                 Polydimethylsiloxane (PDMS) 
                 TPR/PCP 
               
               
                   
                 Polyvinyl Alcohol (PVA) 
                 TPV 
               
               
                   
                 Polyvinyl Pyrrolidone (PVP) 
                 TPV 
               
               
                   
                 Cycloolefin copolymer (COC) 
                 TPV 
               
               
                   
                 Polyurethane (PU) 
                 TPP 
               
               
                   
                 Polycarbonate (PC) 
                 TPEE 
               
               
                   
                 Poly(Ethylene Terephthalate) (PET) 
                 TPEE 
               
               
                   
                 Polyethylene Terephthalate (PETG) 
                 TPEE 
               
               
                   
                 Poly methyl Methacrylate (PMMA) 
                 TPEE/PCP 
               
               
                   
                 Styrene methyl Metacrylate (SMMA) 
                 TPEE 
               
               
                   
                   
               
             
          
         
       
     
         [0021]    The present invention does not particularly limit the material of the extending waveguide  20 . For example, the extending waveguide  20  may be fabricated with a usually used waveguide elements, such as optical fiber, glass tubes, or metallic tubes. Alternatively, the extending waveguide  20  is made of the same waveguide material as the main waveguide  10 . Therefore, various electronic elements can be encapsulated inside the extending waveguide  20 . In one embodiment, the scattering structure  13  includes a nanopowder or a white powder, which is doped on or closed to the surface  12  of the main waveguide  10  or coated on the surface  12  of the main waveguide  10 . In other embodiments, the scattering structure  13  is a white reflective plate or a white coating layer. For example, the white coating layer is formed via smearing a white paint on the surface  12  of the main waveguide  10 . In one embodiment, the scattering structure  13  includes a microstructure, which is disposed on the surface  12  of the main waveguide  10 . For example, the microstructure is a conic microstructure, a semispherical microstructure, a rectangular microstructure, a roughened microstructure, or a combination thereof. 
         [0022]    The flexible waveguide material used by the present invention has flexibility, plasticity and weathering resistance and is suitable to be fabricated into a one-piece component. The flexible waveguide material used by the present invention can be used to encapsulate and protect various electronic components and is suitable to be used in various locations. Refer to  FIG. 2  for yet another embodiment of the present invention. In the embodiment shown in  FIG. 2 , the main waveguide  10  encapsulates at least one solar cell  30 , which is disposed on or close to the side surface  14  of the main waveguide  10  or disposed on or close to the surface  12  of the main waveguide  10  and is not shaded by the scattering structure  13 . However, the present invention does not limit that the solar cell  30  must be disposed on or close to the side surface  14  of the main waveguide  10  or disposed on or close to the surface  12  of the main waveguide  10 . The extending waveguide  20  is also fabricated with the abovementioned soft waveguide material and encapsulates an electronic element  40 , such as an illumination element. The electronic element  40  is disposed on at least one surface of the extending waveguide  20  or embedded inside the extending waveguide  20 , electrically connected with the solar cell  30 . In one embodiment, the main waveguide  10  is doped with a luminescent material or luminescent quantum dots, which absorb shorter-wavelength incident light (such as ultraviolet light) and convert the shorter-wavelength light into longer-wavelength light (such as infrared light), whereby to enhance the power generation efficiency of the solar cell. 
         [0023]    It should be noted: the solar cell can be electrically connected with a rechargeable battery, which stores the power generated by the solar cell and provides power for an illumination element (such as a light emitting diode module) to illuminate indoors at night or on a cloudy day. In one embodiment, the extending waveguide  20  further encapsulates a sensing element, which detects the illuminance variation of the illuminated area and determines whether to turn on the illumination element. The abovementioned sensing element may be a RFID device, a detector or another electronic element. The persons with ordinary knowledge in the art should be able to modify or vary the embodiments without departing from the spirit of the present invention. 
         [0024]    Refer to  FIG. 3  for still another embodiment of the present invention. In the embodiment shown in  FIG. 3 , at least one surface of the main waveguide  10 , e.g. at least one of the incident face  11  and the side surface  14  of the main waveguide  10 , is overlaid with a protection layer  16  to enhance the stain resistance of the illumination system. The protection layer  16  is made of at least one transparent antifouling plastic material having a lower refractivity than the main waveguide  10 , which is selected from a group consisting of ethylene-tetra-fluoro-ethylene (ETFE), ethylene-chlorotrifluororthylene (ECTFE), polytetrafluoroethylene (PTFE), fluorinated Ethylene Propylene (FEP), polyethylene terephthalate (PET), and polycarbonate (PC). 
         [0025]    Below is described a method for manufacturing an illumination system according to one embodiment of the present invention. The waveguide material used by the present invention is at least one selected from a group consisting of polystyrene (PS), polycarbonate (PC), polyurethane (PU), cycloolefin copolymer (COC), poly(ethylene terephthalate) (PET), poly methyl methacrylate (PMMA), polyethylene terephthalate (PETG), styrene methyl metacrylate (SMMA), styrene-ethylene/butylene-styrene (SEBS), polyvinyl Alcohol (PVA), polyvinyl pyrrolidone (PVP), and polydimethylsiloxane (PDMS). In one embodiment, PDMS is used as the waveguide material because its plasticity, high transparency and high flexibility are favorable to manufacture an illumination system that guides solar light for illumination. A waveguide material is prepared beforehand: absorb an appropriate amount of PDMS; 
         [0026]    add a curing agent to PDMS by a ratio (for example, the volume ratio of PDMS to the curing agent is 10:1); agitate the mixture uniformly; keep the mixture still for a period of time, or place the mixture in a vacuum chamber to remove bubbles, wherein the curing agent is not limited to a light curing agent or a thermal curing agent. 
         [0027]    Firstly, provide an extending waveguide having an illuminating surface, wherein the present invention does not particularly limit the material of the extending waveguide. In one embodiment, the bubble-removed waveguide material is poured into an extending mold and heated at a temperature of 90-120° C. to cure the waveguide material and obtain an extending waveguide, wherein the extending waveguide uses the same material as the main waveguide. Next, place one end of the extending waveguide, which is opposite to the illuminating surface, in a mold. Next, fill a waveguide material into the mold and cure the waveguide material to form a main waveguide and join the extending waveguide with the main waveguide, wherein the main waveguide includes an incident face, a surface opposite the incident face and a scattering structure disposed on or close to the surface of the main waveguide, and wherein the scattering structure does not shade a joint interface between the extending waveguide and the main waveguide. Thereby is completed the illumination system shown in  FIG. 1 a    or  FIG. 1   b.    
         [0028]    In one embodiment, after a portion of the extending waveguide is placed in a mold, a solar cell is positioned inside the mold to dispose the solar cell on or close to the side surface of the main waveguide or dispose the solar cell on or close to the surface of the main waveguide, wherein the scattering structure does not shade the solar cell, and wherein the side surface is connected with al least one of the incident face and the surface of the main waveguide. Besides, while the bubble-removed waveguide material is poured into the extending mold, an electronic element is positioned inside the extending mold to dispose the electronic element on at least one surface of the extending waveguide or embed the electronic element inside the extending waveguide, wherein the electronic element is electrically connected with the solar cell. Thereby is completed an illumination system shown in  FIG. 2  or  FIG. 3 . In one embodiment, a rechargeable battery is electrically connected with the solar cell. 
         [0029]    In one embodiment, the waveguide material is blended with a nanopowder to form a nanopowder-containing mixture liquid. For example, mix TiO2 with PDMS uniformly by a ratio of TiO2: PDMS=0.5 g: 1 mL; next, mix the nanopowder-containing mixture liquid with a curing agent uniformly by a ratio of PDMS: curing agent=10:1; next, pour or smear the nanopowder and curing agent-containing mixture liquid on the bottom of the mold. After the waveguide material is cured, a scattering structure is formed on or close to the surface of the main waveguide. In other words, the scattering structuring is formed on an internal side near the surface of the main waveguide or smeared on the surface of the main waveguide. It is easily appreciated: the persons with ordinary knowledge of the art can replace the abovementioned nanopowder with a white powder to achieve the same scattering effect without departing from the spirit of the present invention. However, the present invention does not limit that the scattering structure must be fabricated with the abovementioned nanopowder or white powder. In one embodiment, one inner wall of the mold has a negative microstructure used to form a corresponding microstructure on the surface of the main waveguide, wherein the microstructure may be a conic microstructure, a semispherical microstructure, a rectangular microstructure, a roughened microstructure, or a combination thereof. 
         [0030]    In one embodiment, one inner wall of the mold has a curved surface, a plane or a combination thereof to form a corresponding curve surface, a plane or a combination thereof on the main waveguide. In one embodiment, a protection layer is formed on at least one surface of the main waveguide to enhance the stain resistance of the illumination system, wherein the protection layer is made of at least one material selected from a group consisting of ethylene-tetra-fluoro-ethylene (ETFE), ethylene-chlorotrifluororthylene (ECTFE), polytetrafluoroethylene (PTFE), fluorinated Ethylene Propylene (FEP), polyethylene terephthalate (PET), and polycarbonate (PC). 
         [0031]    Below are introduced tests for verifying the performance of an illumination system according to one embodiment of the present invention, wherein an illumination system whose main waveguide has an incident face with an area of 10×10 cm 2  is used as the sample. A 150 W halogen lamp with an illuminance of about 120 klx illuminates the illumination system from a position 20 cm away from the incident face of the main waveguide. The detected light transmission performance of the illumination system is listed in Table. 2. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                   
                 Light 
                   
               
               
                   
                   
                 Received 
                 Light Output 
               
               
                   
                 Performance of 
                 by Main 
                 by Extending 
               
               
                   
                 Illumination System 
                 Waveguide 
                 Waveguide 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Average Illuminance (klx) 
                 51 
                 3.9 
               
               
                   
                 Average Light Intensity 
                 600 
                 200 
               
               
                   
                 (W/m 2 ) 
               
               
                   
                   
               
             
          
         
       
     
         [0032]    In the test, the current-voltage relationship of the solar cell is also detected and shown in  FIG. 4 . The open-circuit voltage of the solar cell is 1.008V; the short-circuit current of the solar cell is 0.012 A; and the filling factor (FF) is 0.89, which indicate that the illumination system of the present invention can use a portion of external light to generate electric power and has the efficacy of recycling light energy. 
         [0033]    In the same embodiment, a 100 W LED lamp with an illuminance of about 450 klx is also used to illuminate the illumination system from a position 20 cm away from the incident face of the main waveguide, and the detected light transmission performance is listed in Table. 3. 
         [0000]    
       
         
               
               
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                   
                 Light 
                   
               
               
                   
                   
                 Received 
                 Light Output 
               
               
                   
                 Performance of 
                 by Main 
                 by Extending 
               
               
                   
                 Illumination System 
                 Waveguide 
                 Waveguide 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Average Illuminance (klx) 
                 450 
                 90 
               
               
                   
                 Average Light Intensity 
                 1600 
                 540 
               
               
                   
                 (W/m 2 ) 
               
               
                   
                   
               
             
          
         
       
     
         [0034]    In the test, the current-voltage relationship of the solar cell is also detected and shown in  FIG. 5 . The open-circuit voltage of the solar cell is 1.231V; the short-circuit current of the solar cell is 0.111 A; and the filling factor (FF) is 0.72, which indicate that the illumination system of the present invention can use a portion of external light to generate electric power and has the efficacy of recycling light energy. 
         [0035]    From the above description, it should be easily appreciated: the illumination system of the present invention not only guides external (such as solar light) to illuminate an illuminated area but also uses a solar cell to recycle a portion of external light and generate electric power; the present invention adopts a waveguide material able to encapsulate various electronic elements; therefore, the present invention not only supplies power to the electronic elements but also provides weathering protection for the electronic elements. 
         [0036]    In conclusion, the illumination system of the present invention and the manufacturing method thereof uses a soft waveguide material featuring flexibility, plasticity, and wide-angle light capture capability to guide external light for illumination. The soft waveguide material has superior weathering resistance and can encapsulate various electronic elements or modules. Therefore, the present invention is applicable to various locations. While the waveguide material also encapsulates at least one solar cell, the illumination system of the present invention further has a light energy recycling function. As the soft waveguide material used by the present invention is a high light transmission polymer or an organic polymer, the present invention is environment-friendly, biocompatible and suitable for green energy application.