Patent Publication Number: US-2010128462-A1

Title: Illumination device with selectable optical wavelength conversion

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure generally relates to illumination devices, and particularly to an illumination device configured (i.e., structured and arranged) to be able to output light of different wavelengths according to need. 
     2. Description of Related Art 
     LEDs have recently been used extensively as light sources for illumination devices due to their high luminous efficiency, low power consumption and long working life. In some LED illumination devices, to satisfy certain illumination requirements, light mixing is employed. That is, light having different colors or wavelengths is emitted from different light emitting diodes, and such light is mixed to form light of a desired color or wavelength. However, once the different light emitting diodes of the illumination device are encapsulated together to emit light of a desired color or wavelength, further change in the color or wavelength of the light is not possible. 
     Therefore, what is needed is an illumination device that overcomes the described limitations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Many aspects of the disclosed illumination device 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 present illumination device. 
         FIG. 1  is a schematic view of an illumination device of a first embodiment. 
         FIG. 2  is a schematic view of a variation of the first embodiment of the illumination device. 
         FIG. 3  is a schematic view of an illumination device of a second embodiment. 
         FIG. 4  is a schematic view of a variation of the second embodiment of the illumination device. 
         FIG. 5  is a schematic view of an illumination device of a third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to the drawings to describe various embodiments of the illumination device, in detail. 
     Referring to  FIG. 1 , an illumination device  100  of a first embodiment includes a light source  11 , a light transmissive element  12 , and a driving module  13 . 
     The light source  11  includes a substrate  111 , and a plurality of light emitting diodes  112  arranged on the substrate  111 . The light source  11  can be used for emitting monochromatic light or ultraviolet light. In an exemplary embodiment, the light source  11  emits ultraviolet light, and a full width at half maximum of the ultraviolet light is no more than 30 nanometers (nm). 
     The light transmissive element  12  is arranged at a light emitting side of the light source  11 . The light transmissive element  12  has a light transmittance of at least 70%. Thus, optical loss of the light emitted from the light source  11  in the light transmissive element  12  may be considered to be acceptable. 
     The light transmissive element  12  is generally round. The light transmissive element  12  includes a light transmissive substrate  120 , and an optical wavelength converting substance  121  formed on the substrate  120 , here, as a film. The substrate  120  can be resin, silicone, glass, polyethylene terephthalate, polymethyl methacrylate or polycarbonate. The optical wavelength converting substance  121  can be made of a phosphor substance comprising sulfides, aluminates, oxides, silicates, or nitrides. For example, the optical wavelength converting substance  121  can be made of Ca 2 Al 12 O 19 :Mn, (Ca,Sr,Ba)Al 2 O 4 :Eu, CdS, CdTe, Y 3 A 15 O12Ce 3+ (YAG), Tb 3 Al 5 O 12 :Ce 3+ (YAG), BaMgAl 10 O 17 :Eu 2+ (Mn 2+ , (Ca,Sr,Ba)S:Eu 2+ , (Mg,Ca,Sr,Ba) 2 SiO 4 :Eu 2+ , (Mg,Ca,Sr,Ba) 3 Si 2 O 7 :Eu 2+ , Y 2 O 2 S:Eu 3+ , Ca 8 Mg(SiO 4 ) 4 Cl 2 :Eu 2+ , (Sr,Ca,Ba)Si x O y N z:Eu   2+ , (Ca,Mg,Y)SiwAl x O y N z :Eu 2+ , or CdSe. 
     The light transmissive element  12  is divided into a plurality of optical wavelength converting regions  123 . Each of the optical wavelength converting regions  123  is sector-shaped, and the optical wavelength converting regions  123  are arranged side by side around a center of the light transmissive element  12 . Each optical wavelength converting region  123  includes a sector-shaped part of the substrate  120 , and a sector-shaped part of the optical wavelength converting substance  121  thereon. Here, each optical wavelength converting region  123  has a uniform concentration of optical wavelength converting material in the sector-shaped part of the optical wavelength converting substance  121 . The concentration of each optical wavelength converting region  123  is different from that of all of the other optical wavelength converting regions  123 . Therefore, light passing through the different optical wavelength converting regions  123  is absorbed in varying degrees, and the mixed light output from the different optical wavelength converting regions  123  has different colors or/and chromas. 
     In alternative embodiments, the optical wavelength converting substance  121  of each optical wavelength converting region  123  is a different substance from the optical wavelength converting substance  121  of all of the other optical wavelength converting regions  123 . 
     Alternatively, the optical wavelength converting substance  121  can be omitted. Instead, optical wavelength converting material is mixed in a base material of the substrate  120 . In such case, each of the optical wavelength converting regions  123  has a concentration of optical wavelength converting material different from that of all of the other optical wavelength converting regions  123 . 
     The driving module  13  includes a motor  130  driving a rotatable shaft  131 . The rotatable shaft  131  has one end portion fixed to the center of the light transmissive element  12 , which is, accordingly, rotated thereby. Any one of the optical wavelength converting regions  123  can be selectively positioned opposite to the light source  11 , to receive light emitted from the light source  11  and convert the wavelength of the light to a desired wavelength. In certain embodiments, two or more optical wavelength converting regions  123  can be selectively simultaneously positioned opposite to the light source  11 . 
       FIG. 2  is a schematic view of an illumination device  100   a , which is a variation of the first embodiment. The illumination device  100   a  includes a light source  11 , a light transmissive element  12   a , and a driving module  13 . The light transmissive element  12   a  includes a light transmissive substrate  120   a . The substrate  120   a  has a plurality of receiving holes  122  formed therein. Each of the receiving holes  122  has an optical wavelength converting substance  121  received therein. In the illustrated embodiment, each receiving hole  122  is a blind hole. As such, each receiving hole  122  with the optical wavelength converting substance  121  received therein and a corresponding portion of the substrate  120   a  below the receiving hole  122  cooperatively form an optical wavelength converting region  123   a.    
     The light transmissive element  12   a  can be rotated by the driving module  13 . Any one of the optical wavelength converting regions  123   a  can be selectively positioned opposite to the light source  11 , to receive light emitted from the light source  11  and convert the wavelength of the light to a desired wavelength. In certain embodiments, two or more optical wavelength converting regions  123   a  can be selectively simultaneously positioned opposite to the light source  11 . 
       FIG. 3  is a schematic view of an illumination device  200  of a second embodiment. The illumination device  200  includes a light source  21 , a light transmissive element  22 , and a driving module  23 . 
     The light source  21  is similar to the above-described light source  11 . 
     The light transmissive element  22  is arranged at a light emitting side of the light source  21 , and is rectangular. The light transmissive element  22  includes a light transmissive substrate  220 , and an optical wavelength converting substance  221  formed on the substrate  220  (in this embodiment, in the form of a film). The substrate  220  can be similar to the substrate  120 . The optical wavelength converting substance  221  can be similar to the optical wavelength converting substance  121 . 
     The light transmissive element  22  is divided into a plurality of optical wavelength converting regions  223 . Each of the optical wavelength converting regions  223  is rectangular. In the illustrated embodiment, each optical wavelength converting region  223  is strip-shaped. The optical wavelength converting regions  223  are arranged side by side. Each optical wavelength converting region  223  includes a rectangular (strip-shaped) part of the substrate  220 , and a rectangular (strip-shaped) part of the optical wavelength converting substance  221  thereon. Each optical wavelength converting region  223  has a uniform concentration of optical wavelength converting material in the strip-shaped part of the optical wavelength converting substance  221 . The concentration of each optical wavelength converting region  223  is different from that of all of the other optical wavelength converting regions  223 . Therefore, light passing through the different optical wavelength converting regions  223  is absorbed in varying degrees, and the mixed light output from the different optical wavelength converting regions  223  has different colors or/and chromas. 
     In alternative embodiments, the optical wavelength converting substance  221  of each optical wavelength converting region  223  is a different substance from the optical wavelength converting substance  221  of all of the other optical wavelength converting regions  223 . 
     Alternatively, the optical wavelength converting substance  221  can be omitted. Instead, optical wavelength converting material is mixed in a base material of the substrate  220 . In such case, each of the optical wavelength converting regions  223  has a concentration of optical wavelength converting material different from that of all of the other optical wavelength converting regions  223 . 
     The driving module  23  includes two opposite driving wheels  231 ,  232 . The two driving wheels  231 ,  232  both contact the light transmissive element  22 , such that the light transmissive element  22  can be moved along a common tangent direction of the driving wheels  231 ,  232 . In the illustrated embodiment, the driving wheels  231 ,  232  are in the form of driving cylinders. Any one of the optical wavelength converting regions  223  can be selectively positioned opposite to the light source  21 , to receive light emitted from the light source  21  and convert the wavelength of the light to a desired wavelength. In certain embodiments, two or more optical wavelength converting regions  223  can be selectively simultaneously positioned opposite to the light source  21 . 
       FIG. 4  is a schematic view of an illumination device  200   a , which is a variation of the second embodiment. The illumination device  200   a  includes a light source  21 , a light transmissive element  22   a , and a driving module  23 . The illumination device  200   a  has a configuration similar to the illumination device  200 , differing in that the light transmissive element  22   a  is divided into a plurality of optical wavelength converting regions  223   a  which are arranged in an m×n matrix array. The light transmissive element  22   a  can be linearly driven by the driving module  23 . In a typical embodiment, several of the optical wavelength converting regions  223   a  can be selectively simultaneously arranged opposite to the light source  21 , to receive light emitted from the light source  21  and convert the wavelength of the light to a desired wavelength or wavelengths. 
       FIG. 5  is a schematic view of an illumination device  300  of a third embodiment. The illumination device  300  includes a light source  31 , a light transmissive element  32 , and a driving module  33 . 
     The light source  31  is similar to the above-described light source  11 . 
     The light transmissive element  32  is arranged at a light emitting side of the light source  31 . The light transmissive element  32  is generally round, and includes a plurality of gear teeth (not labeled) on a periphery thereof. The light transmissive element  32  includes a light transmissive substrate  320 , and an optical wavelength converting substance  321  formed on the substrate  320 , here, as a film. The substrate  320  can be similar to the substrate  120 . The optical wavelength converting substance  321  can be similar to the optical wavelength converting substance  121 . 
     The light transmissive element  32  is divided into a plurality of optical wavelength converting regions  323 . Each of the optical wavelength converting regions  323  is generally sector-shaped, and the optical wavelength converting regions  323  are arranged side by side around a center of the light transmissive element  32 . Each optical wavelength converting region  323  includes a generally sector-shaped part of the substrate  320 , and a generally sector-shaped part of the optical wavelength converting substance  321  thereon. Each optical wavelength converting region  323  has a uniform concentration of optical wavelength converting material in the generally sector-shaped part of the optical wavelength converting substance  321 . The concentration of each optical wavelength converting region  323  is different from that of all of the other optical wavelength converting regions  323 . Therefore, light passing through the different optical wavelength converting regions  323  is absorbed in varying degrees, and the mixed light output from the different optical wavelength converting regions  323  has different colors or/and chromas. 
     Alternatively, the optical wavelength converting substance  321  can be omitted. Instead, optical wavelength converting material is mixed in a base material of the substrate  320 . In such case, each of the optical wavelength converting regions  323  has a concentration of optical wavelength converting material different from that of all of the other optical wavelength converting regions  323 . 
     The driving module  33  includes a gear wheel  331  with a plurality of gear teeth, and a motor  332  for rotating the gear wheel  331 . One or more of the gear teeth of the gear wheel  331  are meshed with one or more of the gear teeth of the light transmissive element  32 . Thereby, the light transmissive element  32  is indirectly rotated by the motor  332 . Any one of the optical wavelength converting regions  323  can be selectively positioned opposite to the light source  31 , to receive light emitted from the light source  31  and convert the wavelength of the light to a desired wavelength. In certain embodiments, two or more optical wavelength converting regions  323  can be selectively simultaneously positioned opposite to the light source  31 . 
     In summary, the illumination devices  100 ,  200 ,  300  are equipped with light transmissive elements  12 ,  22 ,  32  having a plurality of optical wavelength converting regions  123 ,  223 ,  323 . One or more of the optical wavelength converting regions  123 ,  223 ,  323  can be selectively positioned opposite to the light sources  11 ,  21 ,  31 , such that the color or/and chroma of the illumination devices  100 ,  200 ,  300  can be flexibly changed according to different requirements. 
     Finally, 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. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.