Study On UV-curing Packing Method Of White LED And Its Optical Property

Under the background of global energy crisis, LED is becoming more and morepopular and has been applied to various fields of our life because of its advantages ofenergy saving. Specifically, white LED used in the illumination field possessestremendous advantages. LED package is an important part of the LED industry andsolidification is an inevitable step of LED packaging process. Currently, the generalapproach of solidification is thermal curing that needs high temperature and spends alot of time which not only wastes lots of energy but also reduces the productivity ofLED. As the light-curing technology has the characteristics of efficiency, enabling,economy, energy saving and environment-friendly, it is expected to replace the LEDthermal curing packaging technology. In the study of LED light-curing package, mostresearch is about the light-curable materials and it has basically meet the requirementsof LED package. In addition to the eligible light-curable materials, packaging processand equipment are also the key factor of LED light-curing package. The LEDlight-curing packaging process and its impact on the optical properties of LED arestudied. The main contributions in this paper are as follows:First of all, according to the existing laboratory equipment, the long-termexperience in LED packaging and the characteristics of light-curing technology, theLED light-curing packaging process which provides evidence for the formulation ofLED light-curing packaging standard is given. Taking the advantage of light-curingtechnology, the way of phosphor coating is changed and the phosphor slice isfabricated, as a result the life and color consistency of LED is improved.Secondly, the impact of light-curing packaging process parameters on the opticalperformance of LED is studied. The curing time and the proportion of initiator aremainly studied with the controlling variables method and ageing test is taken after the packaging with the two parameters are finished and the photometric and colorimetricparameters of the LED is measured regularly. The experiment results show that asmaller curing time should be chosen when using the glue employed in theexperiment in the case of meeting the requirement of the physical and mechanicalproperties of LED package, the initiator content should be about3%to5%and theoptimal performance is acquired when it is4%. Depending on the principles of optics,the impact of the curing time and the proportion of initiator on the opticalperformance of LED are investigated and the appropriate curing time and theproportion of initiator are determined which is instructive for the application oflight-curing technology in LED packaging.Lastly, the light-curing machine used for the LED light-curing packageindustrialization is designed, which is the preparation of the realization of LEDlight-curing package industrialization. The light source of the light-curing machine ismetal halid lamp, so that the light source with different emission wavelength can bechosen depends on the different absorption wavelength of the initiator, consequentlythe light spectrum and the absorption of initiator can be matched maximumly. Thedichroic reflector with the shape of elliptic cylinder is designed as the reflex housingof the light source, it not only improves the utilization of the light source but alsoreduces the curing temperature in the chamber. The light-curing machine has severaldefining features of automation, well-cooling, well-protection of UV overflowingprotective, high utilization rate of light source and so on.