Abstract:
A core-shell fluorescent material and a light source device using the same are disclosed. The core-shell fluorescent material includes a core and a shell for generating an emitting light with wavelength within 520 and 800 nm after absorbing an exciting light with wavelength within 370 and 500 nm. The core may include yellow, green or red fluorescent powder, and the shell includes manganese (IV)-doped fluoride compound. The light source device generally includes the core-shell fluorescent material, a radiation source, leads and a package. The leads provide current to the radiation source and cause the radiation source to emit radiation. The core-shell fluorescent material is coated on the package for receiving the radiation so as to generate a high quality emission served as the desired light source for the field of lighting and displaying.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to a core-shell fluorescent material and a light source device using the same, and more specifically to a core-shell fluorescent material comprising a core having yellow, green or red fluorescent powder and a shell having manganese (IV)-doped fluoride compound specified by a chemical formula A x MF 6-y Z y :Mn 4+ , such that the core-shell fluorescent material may absorb the ultraviolet and blue light to generate white light with high color rendering index. 
         [0003]    2. The Prior Arts 
         [0004]    In recent years, there has been considerable interest in white light-emitting diodes (wLEDs) owing to their long operation lifetime, low energy consumption, high material stability, and environmentally friendly characteristics. Hence, white LEDs are promising candidate to replace conventional incandescent and fluorescent lamps. One of indispensable materials for manufacturing LEDs is the fluorescent material for light conversion, which is strongly related to LEDs&#39; luminous efficiency, stability, color rendering, color temperature and lifetime, especially for the white light LED system using the integrated single chip. 
         [0005]    In general, a white light device needs high color rendering to show the true color of the object. White light can be generated by a combination of blue LED chips coated with the yellow-emitting phosphor Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) or green-emitting phosphor Lu 3 Al 5 O 12 :Ce 3+ (LuAG:Ce 3+ ). Nevertheless, the drawbacks of this method include a low-rendering index and high color temperature due to the deficiency of red emission in the visible spectrum. 
         [0006]    Therefore, it is greatly needed for a new core-shell fluorescent material with hybrid spectrum and a new light source device using the core-shell fluorescent material. The core-shell fluorescent material can be used as one single fluorescent powder for packaging so as to effectively increase color rendering for white light. The core-shell fluorescent material comprises a core having yellow, green or red fluorescent powder, and a shell having manganese (IV)-doped fluoride compound such that an exciting light with wavelength range of 370-500 nm is converted into an emitting light with wavelength in the 520-800 nm range. The light source device manufactured by use of the core-shell fluorescent material provides high quality light source, thereby overcoming the above problem in the prior arts. 
       SUMMARY OF THE INVENTION 
       [0007]    The primary objective of the present invention is to provide a core-shell fluorescent material comprising a core and a shell enclosing the core. The core comprises yellow, green or red fluorescent powder, and the shell comprises manganese (IV)-doped fluoride compound. The manganese (IV)-doped fluoride compound is specified by a chemical formula A x MF 6-y Z y :Mn 4+ , wherein A is selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, or combinations thereof; M is selected from Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or combinations thereof; F is the fluorine element, Z is the halogen element comprising at least one of Cl, Br, I, or combinations thereof; 0&lt;x≦2, 0≦y≦6, and Mn 4+  represents&#39; the tetravalent manganese ion. 
         [0008]    The manganese (IV)-doped fluoride compound of the shell could be efficiently excited in the range of 370-500 nm and presented narrow lines between 520 and 800 nm which can further collocate appropriate fluorescent materials for the application field of lighting or liquid crystal display (LCD), thereby providing light source with specific spectrum such as white light source. 
         [0009]    Additionally, the fluorescent powder of the core comprises at least one of a trivalent cerium-doped (Ce +3 ) metal oxide and a divalent europium-doped (Eu +2 ) compound. The trivalent cerium-doped (Ce +3 ) metal oxide is specified by a chemical formula (Y, Gd, Tb, La, Sm, Pr, Lu) 3 (Sc, Al, Ga) 5 O 12 :Ce +3 . The divalent europium compound comprises at least one of (Sr, Ca)Si 2 O 2 N 2 :Eu +2 , Alpha-SiAlON:Eu +2 , Beta-SiAlON:Eu +2 , (Ba, Sr, Ca) 2 SiO 4 :Eu +2 , (Ba, Sr, Ca) 2 Si 5 N 8 :Eu +2 , (Ca, Sr)AlSiN 3 :Eu +2 . In particular, the core has a particle size within 0.01 μm and 200 μm. 
         [0010]    Another objective of the present invention is to provide a light source device comprising the core-shell fluorescent material, radiation source, leads and a package. The leads provide current to the radiation source and cause the radiation source to emit radiation. The core-shell fluorescent material is coated on the package for receiving the radiation so as to generate a high quality emission. Particularly, the light source device of the present invention may comprise at least one of the yellow, green and red fluorescent materials for receiving the radiation by radiation source and emitting the yellow light, the green light and the red light, respectively. Additionally, the yellow, green and red fluorescent materials are homogeneously mixed and coated on the package such that the specific emitting light is adjusted and served as the high quality light source for the field of lighting and displaying. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The present invention will be apparent to those skilled in the art by reading the following detailed description of a preferred embodiment thereof, with reference to the attached drawings, in which: 
           [0012]      FIG. 1  shows core-shell fluorescent material according to one embodiment of the present invention; 
           [0013]      FIG. 2  shows the core-shell fluorescent material mixed the yellow, green and red fluorescent materials according to the present invention; 
           [0014]      FIG. 3  shows the light source device according to another embodiment of the present invention; 
           [0015]      FIG. 3A  shows the SEM (scanning electronic microscope) micrograph of the core-shell fluorescent material of the present invention; 
           [0016]      FIG. 4  illustrates the result of element analysis of the core-shell fluorescent material “Lu 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4 ” in example 1; 
           [0017]      FIG. 5  shows the excitation and emission spectra of the core-shell fluorescent material “Lu 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4 ” in example 1; 
           [0018]      FIG. 6  shows the excitation and emission spectra of the core-shell fluorescent material “Lu 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4 ” using the precursor “K 2 SiF 6 :Mn +4 ” in different concentrations; 
           [0019]      FIG. 7  shows the excitation and emission spectra of the core-shell fluorescent material “Beta-SiAlON/K 2 SiF 6 :Mn +4 ” in example 2; 
           [0020]      FIG. 8  shows the excitation and emission spectra of the core-shell fluorescent material “Beta-SiAlON/K 2 SiF 6 :Mn +4 ” using the precursor “K 2 SiF 6 :Mn +4 ” in different concentrations; 
           [0021]      FIG. 9  shows the excitation and emission spectra of the core-shell fluorescent material “Y 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4 ” in example 3; 
           [0022]      FIG. 10  shows the excitation and emission spectra of the core-shell fluorescent material “(Ba, Sr, Ca) 2 SiO 4 :Eu +2 /K 2 SiF 6 :Mn +4 ” in example 4; 
           [0023]      FIG. 11  shows the excitation and emission spectra of the core-shell fluorescent material “(Sr, Ca)Si 2 O 2 N 2 :Eu +2 /K 2 SiF 6 :Mn +4 ” in example 5; 
           [0024]      FIG. 12  shows the excitation and emission spectra of the core-shell fluorescent material “(Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2 /K 2 SiF 6 :Mn +4 ” in example 6; and 
           [0025]      FIG. 13  shows the excitation and emission spectra of the core-shell fluorescent material “(Ca, Sr)AlSiN 3 :Eu +2 /K 2 SiF 6 :Mn +4 ” in example 7. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    The present invention may be embodied in various forms and the details of the preferred embodiments of the present invention will be described in the subsequent content with reference to the accompanying drawings. The drawings (not to scale) show and depict only the preferred embodiments of the invention and shall not be considered as limitations to the scope of the present invention. Modifications of the shape of the present invention shall too be considered to be within the spirit of the present invention. 
         [0027]    Please refer to  FIG. 1  illustrating the core-shell fluorescent material according to one embodiment of the present invention. As shown in  FIG. 1 , the core-shell fluorescent material  1  of the present embodiment is generally a kind of phosphor in a form of particle or powder, and specifically comprises a core  10  and a shell  20  coated on the core  10 . The core  10  preferably has a particle size within 0.01 μm and 200 μm and comprises yellow, green or red fluorescent powder, and the shell  20  comprises manganese (IV)-doped fluoride compound. 
         [0028]    Overall speaking, the core-shell fluorescent material  1  of the present invention can be excited by the ultraviolet light and visible light L 1  with wavelength within 370 nm and 500 nm, and then generates the emitting light L 2  with peak wavelength within 520 nm and 800 nm, which is applicable to the light source for lighting or display device. 
         [0029]    More specifically, the yellow, green or red fluorescent powder of the core  10  may comprise at least one of a trivalent cerium-doped (Ce +3 ) metal oxide and a divalent europium-doped (Eu +2 ) compound. The trivalent cerium-doped metal oxide is specified by a chemical formula (Y, Gd, Tb, La, Sm, Pr, Lu) 3 (Sc, Al, Ga) 5 O 12 :Ce +3 . The divalent europium compound comprises at least one of (Sr, Ca)Si 2 O 2 N 2 :Eu +2 , Alpha-SiAlON:Eu +2 , Beta-SiAlON:Eu +2 , (Ba, Sr, Ca) 2 SiO 4 :Eu +2 , (Ba, Sr, Ca) 2 Si 5 N 8 :Eu +2 , (Ca, Sr)AlSiN 3 :Eu +2 . 
         [0030]    Specifically, the manganese (IV)-doped fluoride compound of the shell  20  is specified by a chemical formula A x MF 6-y Z y :Mn 4+ , wherein A is selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, or combinations thereof; M is selected from Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or combinations thereof; F is the fluorine element, Z is the halogen element comprising at least one of Cl, Br, I, or combinations thereof; 0&lt;x≦2, 0≦y≦6, and Mn 4+  represents the tetravalent manganese ion. 
         [0031]    To further adjust the spectrum of the emitting light L 2  to form hybrid light for a specific spectrum like white light, please refer to  FIG. 2  showing the core-shell fluorescent material mixed with the yellow, green and red fluorescent materials according to the present invention. In other words, the present invention may further comprise at least one of the yellow fluorescent material  22 , the green fluorescent material  24  and the red fluorescent material  26 , which receive the exciting light L 1  and then emit yellow, green and red light, respectively. 
         [0032]    More specifically, the above yellow fluorescent material  22  comprises at least one of Y 3 Al 5 O 12 :Ce +3 , Alpha-SiAlON:Eu +2  or (Ba, Sr, Ca) 2 SiO 4 :Eu +2 . 
         [0033]    The green fluorescent material comprises at least one of Lu 3 Al 5 O 12 :Ce +3 , Beta-SiAlON:Eu +2  or (Sr, Ca)Si 2 O 2 N 2 :Eu +2 . The red fluorescent material comprises at least one of (Ba, Sr, Ca) 2 Si 5 N 8 :Eu +2  or (Ca, Sr)AlSiN 3 :Eu +2 . 
         [0034]    Further refer to  FIG. 3  showing the light source device according to another embodiment of the present invention. The light source device  2  of the present embodiment generally comprises the core-shell fluorescent material  1 , a radiation source  30 , the leads CN and a package B. 
         [0035]    The leads CN provide current to the radiation source  30  so as to generate the radiation light L 1 , and the core-shell fluorescent material  1  is coated on the package B for receiving the radiation light L 1  to generate emission L 3  such as white light. 
         [0036]    The package B encloses the radiation source  30  and the leads CN for protection, and is generally formed of highly transparent and electrically insulating resin or glass. 
         [0037]    The feature of the core-shell fluorescent material  1  of the present embodiment is similar to the embodiment in  FIGS. 1 and 2 , and the detailed description is thus omitted. 
         [0038]    Accordingly, the light source device  2  of the present embodiment may comprise at least one of the yellow fluorescent material  22 , the green fluorescent material  24  and the red fluorescent material  26 . Since the yellow fluorescent material  22 , the green fluorescent material  24  and the red fluorescent material  26  are similar to the previous embodiment in  FIGS. 1 and 2 , the technical aspect is omitted hereafter. 
         [0039]    Therefore, the above emitting light L 3  can be applied in lighting and TV backlighting. 
         [0040]    More specifically, the radiation source  30  comprises at least one light emitting diode (LED), at least one laser diode (LD), at least one organic light emitting diode (OLED), at least one cold cathode fluorescent lamp (CCFL), or at least one external electrode fluorescent lamp (EEFL). 
         [0041]    In order to more clearly explain the aspects of the present invention, especially the overall fluorescent effect on the exciting light L 1  with wavelength within 370 nm and 500 nm by the core-shell fluorescent material  1  comprising the core  10  and the shell  20 , some specific examples 1-10 will be described in detail in the following. However, it should be noted that, examples 1-10 are only illustrative, but not intended to limit the scope of the present invention. 
         [0042]    First of all, the core-shell fluorescent material  1  used in example 1 primarily comprises the core  10  formed of Lu 3 Al 5 O 12 :Ce +3  and the shell  20  formed of K 2 SiF 6 :Mn +4 . 5-10 g SiO 2  was dissolved in 100 mL-1 L HF (hydrogen fluoride) solution, and then 5-10 g Lu 3 Al 5 O 12 :Ce +3  powder are added. As 20-50 g KMnO 4  was dissolved in solution, the color of solution quickly turned to deep purple. Then 10-60 mL H 2 O 2  was added until core-shell phosphor was formed. Some subsequent tests and analyses are performed, including SEM (scanning electronic microscope) shown in  FIG. 3A , the element analysis shown in  FIG. 4 , and the excitation spectrum PLE and the emission spectrum PL shown in  FIG. 5 .  FIG. 3A  shows the core-shell fluorescent material  1  is in a form of irregular particle or powder with a size 15-30 μm.  FIG. 4  clearly illustrates the core-shell fluorescent material  1  contains some elements like Lu, Al, O, Ce, K, Si, F and Mn.  FIG. 5  shows the spectra of the excitation and the emission for the core-shell fluorescent material Lu 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4 . Specifically, the spectrum of the excitation comprises two peaks within 300-535 nm, which meets commonly used blue LED chip L 1  with wavelength within 400-460 nm. In the spectrum of the emission L 2  generated by Lu 3 Al 5 O 12 :Ce +3  and K 2 SiF 6 :Mn +4 , the red light component is generated by K 2 SiF 6 :Mn +4  of the shell  20 , and has wavelength within 600-700 nm, especially with peak wavelength at 630 nm. That is, it is narrow red light. Therefore, K 2 SiF 6 :Mn +4  is a fluorescent material for highly saturated red light. Additionally, the green light component of the emission spectrum comes from Lu 3 Al 5 O 12 :Ce +3  of the core  10 , and has wavelength within 480-750 nm, especially with peak wavelength at 550 nm. Thus, Lu 3 Al 5 O 12 :Ce +3  is a fluorescent material for emitting green light. 
         [0043]    Next,  FIG. 6  shows the spectra of the excitation and the emission for the core-shell fluorescent material using the precursor K 2 SiF 6 :Mn +4  in different concentrations 0.2M, 0.4M and 0.8M. As a result, the desired emission can be adjusted by the precursor in different concentrations so as to accord with the requirement of high color rendering by use of only one fluorescent material to collocate the blue light LED. 
         [0044]    In example 2, the core  10  is formed of “Beta-SiAlON:Eu +2 ” and the shell  20  is formed of “K 2 SiF 6 :Mn +4 ”. In stoichiometric ratio, 5-10 g SiO 2  was dissolved in 100 mL-1 L HF (hydrogen flouride) solution, and then 5-10 g Beta-SiAlON:Eu +2  powder are added. As 20-50 g KMnO 4  was dissolved in solution, the color of solution quickly turned to deep purple. Then 10-60 mL H 2 O 2  was added until core-shell phosphor was formed. 
         [0045]    Some tests and analyses are then performed.  FIG. 7  is the spectra of the excitation and the emission for the present core-shell fluorescent material. The corresponding component for the excitation in the spectrum is formed of two peaks with wavelength within 300-535 nm. Accordingly, this excitation is applicable to the traditional blue LED chip with wavelength within 440-460 nm. The component of the emitting light in the spectrum comes from “Beta-SiAlON:Eu +2 ” and “K 2 SiF 6 :Mn +4 ”. More specifically, the red light component is generated by K 2 SiF 6 :Mn +4  of the shell  20 , and has wavelength within 600-700 nm, especially with peak wavelength at 630 nm as narrow red light. It is thus a fluorescent material for highly saturated red light. The green light component is generated by Beta-SiAlON:Eu +2  of the core  10 , and has wavelength within 480-750 nm, especially with peak wavelength at 540 nm. Thus, Beta-SiAlON:Eu +2  is a green light material. 
         [0046]    In addition,  FIG. 8  shows the spectra of the excitation and the emission for the core-shell fluorescent material using the precursor K 2 SiF 6 :Mn +4 ” in different concentrations including 0.2M, 0.4M, 0.6M, 0.8M, 1.0M and 1.2M. As a result, the desired emission can be adjusted by the precursor in different concentrations so as to accord with the requirement of high color rendering by use of only one fluorescent material to collocate the blue light LED. 
         [0047]    For example 3, the core-shell fluorescent material  1  is formed of “Y 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4 ”. In stoichiometric ratio, 5-10 g SiO 2  was dissolved in 100 mL-1 L HF (hydrogen flouride) solution, and then 5-10 g Y 3 Al 5 O 12 :Ce +3  powder are added. As 20-50 g KMnO 4  was dissolved in solution, the color of solution quickly turned to deep purple. Then 10-60 mL H 2 O 2  was added until core-shell phosphor was formed. Finally, some tests and analyses are then performed.  FIG. 9  shows the spectra of the excitation and the emission for the core-shell fluorescent material Y 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4 . The corresponding component for the excitation in the spectrum is formed of two peaks with wavelength within 300-535 nm. Accordingly, this excitation is applicable to the traditional blue LED chip with wavelength within 440-460 nm. The component of the emission in the spectrum comes from “Y 3 Al 5 O 12 :Ce +3 ” and “K 2 SiF 6 :Mn +4 ”. More specifically, the red light component is generated by K 2 SiF 6 :Mn +4  of the shell  20 , and has wavelength within 600-700 nm, especially with peak wavelength at 630 nm as narrow red light. It is thus a fluorescent material for highly saturated red light. The green light component is generated by Y 3 Al 5 O 12 :Ce +3  of the core  10 , and has wavelength within 480-750 nm, especially with peak wavelength at 560 nm. Thus, Y 3 Al 5 O 12 :Ce +3  is a yellow light material. 
         [0048]    The assembly of the core  10  and the shell  20  in example 4 is (Ba, Sr, Ca) 2 SiO 4 :Eu +2 /K 2 SiF 6 :Mn +4 . In stoichiometric ratio, 5-10 g SiO 2  was dissolved in 100 mL-1 L HF (hydrogen flouride) solution, and then 5-10 g (Ba, Sr, Ca) 2 SiO 4 :Eu +2  powder are added. As 20-50 g KMnO 4  was dissolved in solution, the color of solution quickly turned to deep purple. Then 10-60 mL H 2 O 2  was added until core-shell phosphor was formed.  FIG. 10  is the spectra of the excitation and the emission for the present core-shell fluorescent material (Ba, Sr, Ca) 2 SiO 4 :Eu +2 /K 2 SiF 6 :Mn +4 . The corresponding component for the excitation in the spectrum is formed of two peaks with wavelength within 300-535 nm. Accordingly, this excitation is applicable to the traditional blue LED chip with wavelength within 440-460 nm. The component of the emission in the spectrum comes from (Ba,Sr,Ca) 2 SiO 4 :Eu +2  and K 2 SiF 6 :Mn +4 . The red light component is generated by K 2 SiF 6 :Mn +4  of the shell  20 , and has wavelength within 600-700 nm, especially with peak wavelength at 630 nm as narrow red light. It is thus a fluorescent material for highly saturated red light. The green light component is generated by (Ba, Sr, Ca) 2 SiO 4 :Eu +2  of the core  10 , and has wavelength within 480-750 nm, especially with peak wavelength at 570 nm. Thus, (Ba, Sr, Ca) 2 SiO 4 :Eu +2  is a yellow light material. 
         [0049]    In example 5, the assembly of the core  10  and the shell  20  is (Sr, Ca)Si 2 O 2 N 2 :Eu +2 /K 2 SiF 6 :Mn +4 . In stoichiometric ratio, 5-10 g SiO 2  was dissolved in 100 mL-1 L HF (hydrogen flouride) solution, and then 5-10 g (Sr, Ca)Si 2 O 2 N 2 :Eu +2  powder are added. As 20-50 g KMnO 4  was dissolved in solution, the color of solution quickly turned to deep purple. Then 10-60 mL H 2 O 2  was added until core-shell phosphor was formed.  FIG. 11  is the spectra of the excitation and the emission for the present core-shell fluorescent material (Sr,Ca)Si 2 O 2 N 2 :Eu +2 /K 2 SiF 6 :Mn +4 . The corresponding component for the excitation in the spectrum is formed of two peaks with wavelength within 300-535 nm. Accordingly, this excitation is applicable to the traditional blue LED chip with wavelength within 440-460 nm. The component of the emission in the spectrum comes from (Sr, Ca)Si 2 O 2 N 2 :Eu +2  and K 2 SiF 6 :Mn +4 . The red light component is generated by K 2 SiF 6 :Mn +4  of the shell  20 , and has wavelength within 600-700 nm, especially with peak wavelength at 630 nm as narrow red light. It is thus a fluorescent material for highly saturated red light. The green light component is generated by (Sr, Ca)Si 2 O 2 N 2 :Eu +2  of the core  10 , and has wavelength within 480-750 nm, especially with peak wavelength at 545 nm. Thus, (Sr, Ca)Si 2 O 2 N 2 :Eu +2  is a yellow light material. 
         [0050]    In example 6, the assembly of the core  10  and the shell  20  is (Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2 /K 2 SiF 6 :Mn 4+ . In stoichiometric ratio, 5-10 g SiO 2  was dissolved in 100 mL-1 L HF (hydrogen flouride) solution, and then 5-10 g (Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2  powder are added. As 20-50 g KMnO 4  was dissolved in solution, the color of solution quickly turned to deep purple. Then 10-60 mL H 2 O 2  was added until core-shell phosphor was formed.  FIG. 12  is the spectra of the excitation and the emission for the present core-shell fluorescent material (Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2 /K 2 SiF 6 :Mn +4 . The corresponding component for the excitation in the spectrum is formed of two peaks with wavelength within 300-535 nm. Accordingly, this excitation is applicable to the traditional blue LED chip with wavelength within 440-460 nm. The component of the emission in the spectrum comes from (Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2  and K 2 SiF 6 :Mn +4 , and has wavelength within 500-750 nm, especially with peak wavelength at 630 nm. 
         [0051]    In example 7, the assembly of the core  10  and the shell  20  is (Ca, Sr)AlSiN 3 :Eu +2 /K 2 SiF 6 :Mn 4+ . In stoichiometric ratio, 5-10 g SiO 2  was dissolved in 100 mL-1 L HF (hydrogen flouride) solution, and then 5-10 g (Ca, Sr)AlSiN 3 :Eu +2  powder are added. As 20-50 g KMnO 4  was dissolved in solution, the color of solution quickly turned to deep purple. Then 10-60 mL H 2 O 2  was added until core-shell phosphor was formed.  FIG. 13  is the spectra of the excitation and the emission for the present core-shell fluorescent material (Ca, Sr)AlSiN 3 :Eu +2 /K 2 SiF 6 :Mn +4 . The corresponding component for the excitation in the spectrum is formed of two peaks with wavelength within 300-535 nm. Accordingly, this excitation is applicable to the traditional blue LED chip with wavelength within 440-460 nm. The component of the emission in the spectrum comes from (Ca, Sr)AlSiN 3 :Eu +2  and K 2 SiF 6 :Mn +4 , and has wavelength within 500-750 nm, especially with peak wavelength at 630 nm. 
         [0052]    For example 8, the assembly of (Lu 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn 4+ ) is packaged. Table 1 shows the test result for the fluorescent materials in the above examples after being packaged. Comparative examples 1-5 are implemented by using single fluorescent powder, and the 460 nm blue LED chip is used to collocate Lu 3 Al 5 O 12 :Ce +3 , Y 3 Al 5 O 12 :Ce +3 , (Sr, Ca)Si 2 O 2 N 2 :Eu +2 , (Ba, Sr, Ca) 2 SiO 4 :Eu +2  and Beta-SiAlON:Eu +2 , respectively. However, example 8 is packaged by employing the core-shell fluorescent material Lu 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4  manufactured in example 1 and the 460 nm blue LED chip. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 assembly 
                 CRI 
               
               
                   
               
             
             
               
                 Comparative 
                 460 nm blue LED chip + Lu 3 Al 5 O 12 :Ce +3   
                 72 
               
               
                 example 1 
                 fluorescent powder 
                   
               
               
                 Comparative 
                 460 nm blue LED chip + Y 3 Al 5 O 12 :Ce +3   
                 75 
               
               
                 example 2 
                 fluorescent powder 
                   
               
               
                 Comparative 
                 460 nm blue LED chip + (Sr, Ca)Si 2 O 2 N 2 :Eu +2   
                 68 
               
               
                 example 3 
                 fluorescent powder 
                   
               
               
                 Comparative 
                 460 nm blue LED chip + (Ba, Sr, Ca) 2 SiO 4 :Eu +2   
                 72 
               
               
                 example 4 
                 fluorescent powder 
                   
               
               
                 Comparative 
                 460 nm blue LED chip + Beta-SiAlON:Eu +2   
                 60 
               
               
                 example 5 
                 fluorescent powder 
                   
               
               
                 Example 8 
                 460 nm blue LED chip + 
                 80 
               
               
                   
                 Lu 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4   
               
               
                   
               
             
          
         
       
     
         [0053]    As a result, the packages of comparative examples 1-5 have color rendering index (CRI) within 60-75, but the package using the core-shell fluorescent material Lu 3 Al 5 O 12 :Ce +3 /K 2 SiF 6 :Mn +4  as a single one fluorescent powder can improve CRI up to 80. 
         [0054]    Additionally, example 9 employs the core-shell fluorescent material (Ca,Sr,Ba) 2 Si 5 N 8 :Eu +2 /K 2 SiF 6 :Mn +4 , and the result is shown in Table 2. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                   
                 assembly 
                 CRI 
               
               
                   
               
             
             
               
                 Comparative 
                 460 nm blue LED chip + Lu 3 Al 5 O 12 :Ce +3  fluorescent  
                 84 
               
               
                 example 6 
                 powder + (Ca,Sr,Ba) 2 Si 5 N 8 :Eu + 2  fluorescent powder 
                   
               
               
                 Example 9 
                 460 nm blue LED chip + Lu 3 Al 5 O 12 :Ce +3  fluorescent  
                 87 
               
               
                   
                 powder + (Ca,Sr,Ba) 2 Si 5 N 8 :Eu +2 /K 2 SiF 6 :Mn +4   
               
               
                   
               
             
          
         
       
     
         [0055]    In Table 2, comparative example 6 uses the 460 nm blue LED chip collocating Lu 3 Al 5 O 12 :Ce +3  fluorescent powder and (Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2  fluorescent powder so as to perform packaging. Example 9 uses the core-shell fluorescent material (Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2 /K 2 SiF 6 :Mn +4  manufactured in example 6, which collocates Lu 3 Al 5 O 12 :Ce +3  fluorescent powder and the 460 nm blue LED chip, so as to perform packaging. The result shows that the package of comparative examples 6 has color rendering index (CRI)  84 , but the package using the core-shell fluorescent material (Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2 /K 2 SiF 6 :Mn +4  and Lu 3 Al 5 O 12 :Ce +3  fluorescent powder can increase CRI up to 87. Therefore, the core-shell fluorescent material (Ca, Sr, Ba) 2 Si 5 N 8 :Eu +2 /K 2 SiF 6 :Mn +4  can greatly increase CRI. 
         [0056]    Finally, example 10 shows the result for the core-shell fluorescent material (Ca, Sr)AlSiN 3 :Eu +2 /K 2 SiF 6 :Mn +4 , as shown in Table 3. 
         [0000]    
       
         
               
               
               
             
           
               
                 TABLE 3 
               
               
                   
               
               
                   
                 assembly 
                 CRI 
               
               
                   
               
             
             
               
                 Comparative 
                 460 nm blue LED chip + Lu 3 Al 5 O 12 :Ce +3   
                 85 
               
               
                 example 7 
                 fluorescent powder + (Ca,Sr)AlSiN 3 :Eu +2   
                   
               
               
                   
                 fluorescent powder 
                   
               
               
                 Example 10 
                 460 nm blue LED chip +  
                 88 
               
               
                   
                 Lu 3 Al 5 O 12 :Ce +3  fluorescent 
                   
               
               
                   
                 powder + (Ca, Sr)AlSiN 3 :Eu +2 /K 2 SiF 6 :Mn +4   
               
               
                   
               
             
          
         
       
     
         [0057]    Comparative example 7 uses the 460 nm blue LED chip collocating Lu 3 Al 5 O 12 :Ce +3  fluorescent powder and (Ca, Sr)AlSiN 3 :Eu +2  fluorescent powder so as to perform packaging. Example 10 uses the core-shell fluorescent material (Ca, Sr)AlSiN 3 :Eu +2 /K 2 SiF 6 :Mn +4  manufactured in example 7, which collocates Lu 3 Al 5 O 12 :Ce +3  fluorescent powder and the 460 nm blue chip, so as to perform packaging. The result shows that the package of comparative examples 7 has CRI 85, but the package using the core-shell fluorescent material (Ca, Sr)AlSiN 3 :Eu +2 /K 2 SiF 6 :Mn +4  fluorescent powder can increase CRI up to 88. Therefore, the core-shell fluorescent material (Ca, Sr)AlSiN 3 :Eu +2 /K 2 SiF 6 :Mn +4  can greatly increase CRI. 
         [0058]    From the above mention, one primary feature of the present invention is that the core-shell fluorescent material comprising the core and the shell can afford to adjust the fluorescent effect, particularly, the core comprising yellow light, green light or red light fluorescent powder, and the shell comprising manganese (IV)-doped fluoride compound. Moreover, the present invention may further comprise at least one of yellow light, green light or red light fluorescent materials for receiving the excitation and emission yellow light, green light or red light, respectively, so as to adjust the resultant emission having the specific hybrid spectrum as high quality color light like white light. Additionally, another aspect of the present invention is that the core-shell fluorescent material is used to manufacture the light source device having high color rendering index for providing the desired light source for lighting and TV backlighting. 
         [0059]    Although the present invention has been described with reference to the preferred embodiments, it will be understood that the invention is not limited to the details described thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.