LED Package On Transparent Substrate With High Luminous Efficiency

The main purpose of the paper is to designer and implement a new LED filament bulb,and improve the luminous efficiency of LED with a transparent substrate is used for the package material.the current development state and some problems of LED package technology is discussed deeply.And a research has been done on LED filament bulb’ packaging structure and the parameters of materials for the best LED light color performance and thermal dissipation performance with the methods of theoretical analysis, simulation combine to practice. LED filament bulb with higher efficiency in transparent substrate is implemented and tested.The results of analysis and test are showing that:(1)It just choice the alumina substrate with the thermal conductivity is 20W/(m·K),the thermal conductivity glue withe the thermal conductivity is 10 to 64W/(m·K) can meet the requirements of small power LED chip packaging.Generally,in order to avoid solid crystal glue immerse LED chip to result a short circuit,the solid crystal layer thickness should be less than the LED chip’.When the thickness of transparent substrate is 0.2mm,the thermal dissipation of LED can be improved by increase the thickness of the solid crystal layer.(2)When the thickness of LED substrate is increased,the working temperature of the LED chip is lower.In order to avoid blue leaked,glare and cost savings,we should appropriate to reduce the thickness of LED substrate,so the thickness of the transparent substrate is 0.02 mm was selected.(3)package of a new LED filament bulb with high efficiency in transparent substrate is implemented.Base on the ANSYS simulate of LED,a comprehensive and detailed design is done about the technology of LED chip packaging.Then,the screen-printing technology is used to prepare the packaging PCB,LED chip solid crystal and wire bonding,fluorescent glue deployment and coating step by step.Final,a LED filament bulb is made of chip and flip chip packaged in different transparent substrate with high luminous efficiency was implemented.(4)The performance of the filament package on transparent substrate with high luminous efficiency such as light color electrical performance,aging resistance,thermal infrared images and platinum thermal resistance are tested.The results of the filament bulb(chip/flip chip packaging on glass)are that flux:467.29lm/230.802lm;luminous efficiency:110.06/118.36lm/W; correlated color temperature:3172K/3158K;color rendering index:84.1/82.7;color purity:34.9%/37.4%.And the results the filament bulb(chip/flip chip packaging on sapphire)are that flux: 471.69lm/231.375lm;luminous efficiency: 111.79/120.07lm/W; correlated color temperature: 3004K/3048K; color rendering index: 81.9/83.5;color purity:47%/42.2%.(5)Contract with the existing bulbs,the LED filament bulb package on transparent with high efficiency enhance brightness at least 16% than the existing bulbs,and the luminous efficiency has improved by 13%,the color rendering index has improved by 4%.The LED filament bulb package on transparent substrate is deemed to take the place of the incandescent which used by people for100 years,with the characteristics like compact structure,small size,light weight,low cost and high luminous efficiency.