Abstract:
An exemplary illumination device includes a light source and a light-pervious light guiding barrel. The light source is configured for emitting light along a given light path. The light-pervious light guiding barrel receives the light source therein, and the barrel includes light guiding regions with different light directing and/or reflecting capabilities. In addition, the barrel is rotatable relative to the light source such that each of the light guiding regions can be selectively placed on the light path to direct and/or reflect the light from the light source.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The disclosure generally relates to illumination devices, and particularly to an illumination device with adjustable light radiation direction and/or light radiation angle. 
         [0003]    2. Description of Related Art 
         [0004]    Nowadays, light emitting diodes (LEDs) have been used extensively as light sources for illumination devices due to their high luminous efficiency, low power consumption and long lifespan.  FIG. 15  is a diagram illustrating a Lambertian light intensity distribution of a conventional LED. The Full Width at Half Maximum (FWHM) of the LED is in a range from about 0 degrees to about 60 degrees, and also in a range from about 300 degrees to about 360 degrees. That is, the FWHM of the LED is about 120 degrees. The LED is used to provide light with unchangeable light intensity distribution, which may diminish the LED in many applications. 
         [0005]    Therefore, what is needed is an illumination device that overcomes the described limitations. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0007]      FIG. 1  is a schematic, exploded view of an illumination device, according to an exemplary embodiment. 
           [0008]      FIG. 2  is an enlarged cross section of a light guiding barrel of the illumination device of  FIG. 1 , taken from line II-II thereof. 
           [0009]      FIG. 3  is a partial and enlarged cross section of a first light guiding region of the light guiding barrel of  FIG. 2 , the first light guiding region having cylindrical elongated protrusions extending from an interior surface thereof. 
           [0010]      FIG. 4  is a partial and enlarged cross section of a third light guiding region of the light guiding barrel of  FIG. 2 , the third light guiding region having V-shape elongated protrusions extending from an interior surface thereof, and a transverse cross-section of each V-shape elongated protrusion being an isoceles triangle. 
           [0011]      FIG. 5  is similar to  FIG. 4 , but showing the transverse cross-section of each V-shape elongated protrusion being a right triangle. 
           [0012]      FIG. 6  is similar to  FIG. 3 , but showing the first light guiding region having cylindrical elongated protrusions extending from an exterior surface thereof. 
           [0013]      FIG. 7  is a partial and enlarged cross section of a second light guiding region of the light guiding barrel of  FIG. 2 , the second light guiding region having hemicycle-shaped elongated grooves defined in an interior surface thereof. 
           [0014]      FIG. 8  is similar to  FIG. 7 , but showing the second light guiding region having hemicycle-shaped elongated grooves defined in an exterior surface thereof. 
           [0015]      FIG. 9  is similar to  FIG. 4 , but showing the third light guiding region having V-shape elongated protrusions extending from an exterior surface thereof. 
           [0016]      FIG. 10  is an assembled view of the illumination device of  FIG. 1 . 
           [0017]      FIG. 11  is a cross section of the illumination device of  FIG. 10 , taken from line XI-XI thereof. 
           [0018]      FIG. 12  is a diagram illustrating light intensity distribution of the light incident and output from a first light guiding region of  FIG. 3 . 
           [0019]      FIG. 13  is a diagram illustrating light intensity distribution of the light incident and output from a third light guiding region of  FIG. 5 . 
           [0020]      FIG. 14  is a diagram illustrating light intensity distribution of the light incident and output from a second light guiding region of  FIG. 7 . 
           [0021]      FIG. 15  is a diagram illustrating light intensity distribution of a conventional LED. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]    Reference will now be made to the drawings to describe various embodiments of the illumination device, in detail. 
         [0023]    Referring to  FIG. 1 , an illumination device  100 , according to a first embodiment, includes a light source  11  and a light guiding barrel  12  arranged around the light source  11 . The illumination device  100  may further include an actuator  13  for rotating the light guiding barrel  12  or the light source  11 . 
         [0024]    The light source  11  includes a substrate  111 , and at least one solid-state light source  112  arranged on the substrate  111 . In the first embodiment, the solid-state light source  112  is an LED  112  providing a Lambertian light intensity distribution, as shown in  FIG. 15 . The Full Width at Half Maximum (FWHM) of the LED  112  is in a range from about 0 degrees to about 60 degrees, and also in a range from about 300 degrees to about 360 degrees. That is, the FWHM of the LED  112  is about 120 degrees. A Y-central axis of The LED  112  passes through the substrate  111 . The substrate  111  can be a circuit board securing the LED  112 . Heat generated by the LED  112  can be absorbed by the substrate  111 , and then dissipated to ambient air. The light source  11  may further include a heat dissipation device  113 . The heat dissipation device  113  can, for example, include a base  1130  that contacts a side of the substrate  111  away from the LED  112 , and a plurality of heat dissipation fins  1132  extending from the base  1130 . 
         [0025]    The light guiding barrel  12  can be made of resin, silicone, epoxy, polyethylene terephalate, polymethyl methacrylate, and polycarbonate. Alternatively, the light guiding barrel  12  can be made of glass, or other suitable materials. Referring also to  FIG. 2 , the light guiding barrel  12  includes a plurality of light guiding regions, for example, a first region  121 , a second region  122 , and a third region  123 . The light guiding regions  121 ,  122 ,  123  are sequentially arranged around an X-axis of the light guiding barrel  12  to cooperatively form a first accommodating space  120  for receiving the light source  11 . In this embodiment, the light guiding barrel  12  is a substantially cylinder defining the first accommodating space  120  therein. A first end  124  and a second end  126  are at opposite sides of the light guiding barrel  12 . The first end  124  is open, with the first accommodating space  120  being exposed to an exterior of the light guiding barrel  12  thereat. The second end  126  is closed. Each of the first, second, and third regions  121 ,  122 ,  123  spans through an entire axial length of the light guiding barrel  12  including both the first end  124  and the second end  126 . That is, a boundary between every adjacent the light guiding regions  121 ,  122 , and  123  is substantially parallel to the X-axis of the light guiding barrel  12 . A transverse cross section of each region  121 ,  122 ,  123  (e.g., the first region  121 ) is part of an annulus. Said part of an annulus subtends a central angle θ, as shown in  FIG. 2 . The central angle θ may be equal to a viewing angle of the LED  112 . For example, if the LED  112  has a viewing angle of 120 degrees, the light guiding barrel  12  can be divided into three regions (i.e., the first, second, and third regions  121 ,  122 ,  123 ), with each part of the annulus subtending the same central angle θ in the amount of 120 degrees. 
         [0026]    The light guiding barrel  12  includes an interior surface  12 A and an exterior surface  12 B. Each of the first, second, and third regions  121 ,  122 ,  123  includes a part of the interior surface  12 A and a part of the exterior surface  12 B. The light guiding barrel  12  defines a plurality of micro-structures  128  thereon. In this embodiment, the first region  121  has a plurality of cylindrical elongated protrusion  128  extending outwardly from the interior surface  12 A thereof along the X-axis, and the exterior surface  12 B of the first region  121  is a smooth surface, as shown in  FIG. 3 . In addition, each of the interior surface  12 A and the exterior surface  12 B of the second region  122  is a smooth surface. Furthermore, the third region  123  has a plurality of V-shape elongated protrusion  128  extends outwardly from the interior surface  12 A thereof, and the exterior surface  12 B of the second region  123  is a smooth surface, as shown in  FIG. 4 . The V-shape elongated protrusions  128  are evenly distributed on the interior surface  12 A of the third region  123 , and each of the V-shape elongated protrusion  128  extends parallel to the X-axis. In one example, a transverse cross section of each V-shape elongated protrusion  128  is an isoceles triangle, as shown in  FIG. 4 . In another example, a transverse cross section of each V-shape elongated protrusion  128  can be a right triangle, as shown in  FIG. 5 . 
         [0027]    In alternative embodiments, the first region  121  may have a plurality of cylindrical elongated protrusion  128  extends outwardly from the exterior surface  12 B thereof along the X-axis, with the interior surface  12 A of the first region  121  being a smooth surface, as shown in  FIG. 6 . In addition, the second region  122  may have a plurality of hemicycle-shaped elongated grooves  129  defined therein. The hemicycle-shaped elongated grooves  129  may be defined in the interior surface  12 A, and each hemicycle-shaped elongated groove  129  may extend parallel to the X-axis, as shown in  FIG. 7 . Alternatively, the hemicycle-shaped elongated grooves  129  may be defined in the exterior surface  12 B, as shown in  FIG. 8 . Furthermore, the third region  123  may has a plurality of V-shape elongated protrusion  128  extends outwardly from the exterior surface  12 B thereof along the X-axis, as shown in  FIG. 9 . 
         [0028]    The illumination device  100  may further include a bracket  14  for holding the light source  11 . The bracket  14 , for example, may include a main body  140  having a second accommodating space  14 A therein, and two supporting portions  142 . In this embodiment, the main body  140  is in the form of a second cylinder having the second accommodating space  14 A defined therein. The main body  140  has two opposite ends, at each of which the second accommodating space  14 A is exposed to an exterior of the main body  140 . The two supporting portions  142  extend from two opposite inner sides of the main body  140 . Each of the two supporting portions  142  has an elongated groove  1420  defined therein, for fittingly receiving a corresponding side edge of the substrate  111 . The bracket  14  can made of light-pervious material, such as resin, polymer or glass, etc. 
         [0029]    The actuator  13  can be a motor with a central shaft (not visible). The shaft of the motor is coaxial with the X-axis of the light guiding barrel  12 . 
         [0030]    Referring also to  FIGS. 10 and 11 , in assembly, by sliding the opposite side edges of the substrate  111  into the two elongated grooves  1420  of the supporting portions  142 , the light source  11  can be held by the bracket  14  in the second accommodating space  14 A. Then the bracket  14 , together with the light source  11  can be received in the first accommodating space  120  of the light guiding barrel  12 , with the LED  112  positioned on, or adjacent to the X-axis of the light guiding barrel  12 . In the illustrated embodiment, an imaginary center axis of the substrate  111  is coaxial with the X-axis. Accordingly, an imaginary diameter of a base surface of the LED  112  is near and parallel to the X-axis. In addition, the actuator  13  can be coupled to the second end  126  of the light guiding barrel  12 , as shown in  FIG. 10 . Furthermore, two bearings  16  can be provided. The bearings  16  are mounted between the main body  140  and the light guiding barrel  12  at the first end  124  and the second end  126 , respectively. Thereby, the bracket  14  is rotatably coupled to the light guiding barrel  12  through the bearings  16 . 
         [0031]    Referring to  FIG. 11 , in a typical application, the bracket  14  with the light source  11  held thereon is fixed to another object (not shown). The actuator  13  rotates the light guiding barrel  12  counter-clockwise (as viewed in  FIG. 11 , shown by the arrow S). Thus, one or two of the light guiding region(s)  121 ,  122 ,  123  can be selectively arranged opposite to the LED  112 . The selected light guiding regions  121 ,  122 ,  123  thereby receive the light emitted from the light source  11 , and guide a direction of the light accordingly. In one example, as shown in  FIG. 11 , the first region  121  is rotated to face the LED  112 . The light emitted from the LED  112  along a given light path substantially perpendicular to the X-axis passes through the cylindrical elongated protrusions  128  of the first region  121 . The cylindrical elongated protrusions  128  decrease a radiating range of the light along Z-axis directions perpendicular to a XY-plane, the decrease being in positive and negative Z-axis directions.  FIG. 12  shows light intensity distribution of the LED  112  after the light thereof passes through the first region  121 . The FWHM of the LED  112  after the light passing through the first region  121  is about 13 degrees, which is much smaller than the FWHM of the LED  112  before the light passing through the first region  121  (120 degrees). In another example, the third region  123  is rotated to face the LED  112 , the V-shape elongated protrusion  128  of the third region  123  improve an uniformity of the light emitted from the LED  112  when the transverse cross section of each V-shape elongated protrusion  128  is an isoceles triangle. Alternatively, the V-shape elongated protrusions  128  may redirect light generated from the LED  112  to deviate from the XY-plane along positive or negative Z-axis directions perpendicular to the XY-plane, when the transverse cross section of each V-shape elongated protrusion  128  is a right triangle.  FIG. 13  shows light intensity distribution of the LED  112  after the light thereof passes through the third region  123 . 
         [0032]    In yet another example, the second region  122  is rotated to face the LED  112 , the light emitted from the LED  112  along a given light path direction substantially perpendicular to the X-axis passes through the second region  122  with hemicycle-shaped elongated grooves  129  defined in the interior surface  12 A thereof. The hemicycle-shaped elongated grooves  129  can increase a radiating range of the light along Z-axis directions perpendicular to the XY-plane, the increase being in positive and negative Z-axis directions.  FIG. 14  shows light intensity distribution of the LED  112  after the light thereof passes through the second region  122 . The FWHM of the LED  112  after the light passing through the second region  122  is about 127 degrees, which is larger than the FWHM of the LED  112  before the light passing through the second region  122  (120 degrees). 
         [0033]    Therefore, the illumination device  100  may have a selective output light with Page of different light intensity distributions. In one application, the illumination device  100 , for example, may be used to provide overhead lighting when the second region  122  with hemicycle-shaped elongated grooves  129  defined therein is rotated to face the LED  112 . 
         [0034]    In alternative embodiments, the interior surface  12 A and the exterior surface  12 B of the second region  122  may both have hemicycle-shaped elongated grooves  129  defined therein. In such case, the hemicycle-shaped elongated grooves  129  defined in both the interior surface  12 A and the exterior surface  12 B of the second region  122  increase a larger radiating range of the light along Z-axis directions perpendicular to the XY-plane. In other alternative embodiments, the actuator  13  may be coupled to the bracket  14 . Accordingly, in operation, the light guiding barrel  12  is fixed to an object (not shown), and the actuator  13  rotates the bracket  14  with the light source  11  held therein. The LED  112  can thus be selectively positioned opposite to one or two of the light guiding regions  121 ,  122 ,  123 . In still other alternative embodiments, the illumination device  200  may include a plurality of LEDs  112  arranged along the X-axis of the light guiding barrel  12 . 
         [0035]    In summary, the illumination device  100  is equipped with light guiding barrels  12  having a plurality of light guiding regions, and each of the light guiding regions is rotatable relative to the light source  11 , such that a selected one or two of the light guiding regions is positioned opposite to the light source  11 . Thus the light intensity distributions of the illumination device  100  can be flexibly changed according to different requirements, thereby providing rich and colorful illuminating effects as desired. 
         [0036]    It is to be understood that the above-described embodiments are intended to illustrate rather than limit the disclosure. Variations may be made to the embodiments without departing from the spirit of the disclosure as claimed. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.