Study On Health Lighting Luminous Ceramic Technology

Lighting is indispensable to human life.Modern lighting has developed from incandescent lamp,fluorescent lamp and energy-saving lamp to today's LED lighting,which brings great convenience to human life.But there are different problems with each light source,Incandescent lamps have low luminous efficiency,poor photochromism and short service life;fluorescent lamps and energy-saving lamps have mercury pollution environment,obvious sharp blue light peak and low color rendering index;moreover,incandescent lamps,fluorescent lamps and energy-saving lamps are all directly working under power frequency,and their luminous frequency is about 100 Hz,which has stroboscopic hazard.But now LED lighting products which have been widely used have no stroboscopic hazard.In addition,due to the dimmability of LED and the integration of multiple chips in a lamp,it can achieve better color restoration and reduce visual fatigue.Therefore,compared with the traditional light source,LED has more advantages in the control of stroboscopic hazard,color reduction and other aspects,but also more energy-saving and environmental protection.Therefore,LED lighting is the best choice of current lighting technology.However,at present,white LED lighting is mainly formed by blue LED with yellow phosphor.The spectrum range of white LED is narrow,especially the energy of short wave blue light area is relatively concentrated,which is quite different from the actual solar spectrum.There is also obvious glare effect,which makes the LED lighting source have adverse effect on the long-term irradiation of human body.In addition,the existing packaging methods are silica gel and epoxy resin packaging.Silica gel and resin are prone to yellowing under long-term high-temperature working environment,resulting in reduced light efficiency and color coordinate deviation.Due to their poor heat dissipation,they can not meet the requirements of high-power lighting.The ceramic has the advantages of high temperature resistance,corrosion resistance and good thermal conductivity.The combination of ceramics and phosphors can apply the excellent properties of ceramics to the fluorescent materials,and can compound a variety of phosphors.By integrating a variety of chips in the lamp,it can realize the health lighting of imitating natural light spectrum.The main work is as follows:1.Based on commercial alumina ceramics,white LED luminescent ceramics,green LED luminescent ceramics,yellow LED luminescent ceramics and red LED luminescent ceramics were prepared by screen printing by adjusting the content of phosphor and the proportion of low melting point glass powder(hereinafter referred to as low glass powder).The best experimental conditions are determined by means of fluorescence spectrum and absorption spectrum.The optical properties,packaging properties and thermal stability are studied.Under the best experimental conditions,the light efficiency of white LED luminous ceramics is 121 lm/W,the color temperature is 6393 K,the color coordinate is(0.3113,0.3558),the light efficiency of green LED luminous ceramics is 116 lm/W,the color temperature is 6257 k,the color coordinate is(0.2833,0.6515),the luminous efficiency of yellow LED is 138 lm/W,the color temperature is 3745 K,the color coordinate is(0.4405,0.5334),the luminous efficiency of red LED is 25 lm/W,the color temperature is 875 K,and the color coordinate is(0.5449,0.2291).2.On the basis of commercial alumina ceramics,LED light-emitting ceramics are made by screen printing.Selecting the appropriate phosphor,designing the multi light color composite chip,adjusting the proportion of various phosphors to produce the LED light-emitting ceramics.Under the optimal experimental conditions,the light efficiency of the LED light-emitting ceramics is 85 lm/W,the color temperature is 4962 K,the color coordinates are(0.3479,0.3701),the measured color temperature of the natural light(summer noon)is 4890 K,the color coordinates are(0.3492,0.3633),and the spectrum of the LED light-emitting ceramics is in good agreement with that of the natural light.