Preparation Of Phosphor-in-Glass Film For Headlamp And Study On Application Of W-LD

With the continuous development and innovation of the automobile industry,the headlamp which ensures safe driving at night is also devel-oped multiple generations.And light-emitting-diodes（LED）headlamp is most widely used.Compared with LED,laser-dioes（LD）lighting with advantages of more brightness,further irradiation,longer life,and smaller which is more suitable for headlamp.However,color convertion materi-als which is phosphor packaged by epoxy resin for white LED will burned black instantly under laser exciation due to its poor heat dissipa-tion ability.Therefore,it is necessary to explore more reliable color con-verter materials.Compared with other inorganic materials,Phos-phor-in-glass（Pi G）with advantages of easy preparation process,chemi-cal stability and light easy adjustment provides a feasible alternative for the color converter material in white LD.And how to improve the lumi-nous effiency of Pi G has become a hot topic and challenge in recent years for high efficiency white LD.In this paper,the luminous efficacy of sili-cate glass based Pi G is improved by regulating the structure of Pi G.Moreover,low melting temperature and high index of refraction matrix glass is obtained by adjusting the composition of glass which used to prepare Pi G with high luminious efficacy and high color rendering index.This study is mainly divided into three parts.Firstly,a low-temperature and high-pressure technology is raised which success-fully synthesized the Pi G composed by Y₃Al₅O₁₂:Ce³⁺（YAG）phosphor and Si O₂-Al₂O₃-K₂O-Na₂O glass frit.By XRD and SEM analyizing,the effect of this technology and traditional high-temperature atmospher-ic-pressure sintering technology on Pi G structure is studied.In addition,three configurations of transmission,reflection,and total-emission are adopted in w-LD,which can achieve the highest luminous efficiency of77.78 lm/W,178.72 lm/W and 206.35 lm/W respectively.Compared with the traditional high-temperature and normal-pressure method,the sat-uration luminous flux is increased by 4.8%,13.7%,and 14.3%re-spectively for 10%,20%,30%content phosphor Pi G by using the low-temperature and high-pressure method.Secondly,it is found that the matrix glass may erosion the phosphor during the sintering process,so a Si O₂ layer with good optical and stable physical,chemical properties is coated on the surface of YAG particals to protect the phosphor during the sintering process,and then the coated phosphor singtering with glass frit to synthesize high luminous efficacy Pi G.Through SEM and PL spectral analysis,the influence of different process conditions on surface coating is studied.At last,the uniform and intact coating layer which is hardly to peel off under mechanical force and thermal erosion is obtained.In the provious study,luminescence sat-uration of Pi G is achieved at low laser power due to the unsatisfactory thermal conctivity of matrix glass,and the Pi G film with a high thermal conductivity substrate can ameliorate this shortcoming.Hence,using Si O₂-Al₂O₃-K₂O-Na₂O as matrix glass,the Pi G films are prepared by sintering with YAG phosphor before and after coating.The results show that the luminescence efficacy of the Pi G is increased by about 4%after surface coating of phosphor.Thirdly,the color rendering index of the Pi G previous is not ideal.In order to mix the red phosphor which is easy to fail at high temperature,a low-melting temperature glass Si O₂-B₂O₃-Zn O-Na₂O-La₂O₃ is designed whose refractive index is successfully adjusted by the composition.On the basis of the preparation of high luminous efficiency Pi G combining YAG,the red phosphor of Ca Al Si N₃:Eu²⁺（CASN）is successfully doped.By adjusting the ratio of yellow,red phosphor,matrix glass and the thickness of film,a white LD with luminous efficacy of 152lm/W and color rendering index of 81 is obtained.