Preparation And Properties Of Flexible Phosphor Films For White LED

As the fourth generation of illumination source,white light emitting diodes?LEDs?are widely used in indoor and outdoor lighting,display,military and other fields due to their high luminous efficiency,long service life,high chemical stability,low energy consumption,environmental protection and pollution-free.At present,the packaging method of commercial white LEDs is mainly a dispensing method,in which two or more kinds of phosphors are uniformly mixed with organic resin or silicone,and then droped onto the surface of the LED chips,and finally baked and cured.The process of dispensing is very mature,but there are still some problems with this packaging.For example,the phosphor is easy to precipitate,LED light color is inconsistent,LED is difficult to dissipate heat,and the silicone is easily yellowed and cracked after a long time of use.However,the packaging method using the phosphor film can effectively improve the shortcomings of the traditional dispensing method.In this paper,a series of phosphors were prepared by traditional solid phase method,and the prepared phosphors were mixed with silicone to prepare a series of phosphor films by spin coating method.The effects of ion doping on the thermal stability and reliability of the phosphor film and the effects of two different packaging methods of the layered structure phosphor film on the photoelectric performance of the packaged LED device are mainly investigated.The main research work is as follows:1.Y_2.94(Al_1-xGa_x)₅O₁₂:0.06Ce?x=0.05,0.1,0.15,0.2,0.25,0.3?series phosphors were prepared by solid phase method,and the prepared phosphors were prepared into a series of phosphor films by spin coating method.Then,the relationship between the Ga³⁺ion content of YAG:Ce³⁺phosphor in phosphor film and the thermal stability and reliability of the phosphor film was investigated by the high temperature thermal stability test,xenon lamp aging test,high temperature-high humidity test and thermal cycling test,.2.Sr_xCa_1-XAlSiN₃:0.05Eu²⁺?x=0.25,0.4,0.55,0.7,0.85?series phosphors were prepared by solid phase method,and the prepared phosphors were prepared into a series of phosphor films by spin coating method.Then,the relationship between the Sr²⁺ion content of CASN:Eu²⁺phosphor in the phosphor film and the thermal stability and reliability of the phosphor film was investigated by the high temperature thermal stability test,xenon lamp aging test,high temperature-high humidity test and thermal cycling test,3.According to the above findings,the YAG:Ce³⁺?emission wavelength is 530nm?and CASN:Eu²⁺?emission wavelength is 620nm?phosphors with the best reliability were selected to prepare composite phosphor films.Then,the reliability of the composite phosphor film was simply explored,and the application of the white LED device can be realized.YAG:Ce³⁺and CASN:Eu²⁺phosphors were layered to prepare a layered phosphor film?G-R and R-G structures?,in which the content of CASN:Eu²⁺phosphor was different.Finally,the effects of CASN:Eu²⁺phosphor content in phosphor film and two different packaging methods on the photoelectric performance of LED devices were investigated.