The Preparation And Research For A Type Of Chip Scale Packaging LED

With the development of solid-state lighting which has the merit of both energy conservation and environmental protection. The demanding for high power, high luminous efficiency, small volume and low thermal resistance has become the significant obstacles to keeping traditional packaging forms LED moving forward. Chip scale package LED is widely used for the characteristic of minimal volume, lower thermal resistance, 180 degree Beam Angle and more flexible application. According to the present situation of high power LED packaging, this thesis design and develop a kind of chip scale packaging LED, which possesses the characteristics of high power, high luminous efficiency, low thermal resistance, high mechanical strength etc. Meanwhile, comparing this chip scale packaging with traditional packaging LED in the aspect of heat dissipation, optical performance and product application. This thesis is mainly divided into four parts, and the main work is as follows:1. Give a brief introduction to the major form of packaging structure and preparation process for the development history of LED package. Expounding and analyzing the origin of chip scale packaging used in LED industry and its product characteristics in application process. Highlighting the advantage that chip scale packaging used as the LED light source.2. Designing and preparing of a kind of chip scale packaging LED. It's mainly including the process of substrate choosing, designing and manufacturing of circuit layer on substrate surface, mounting, surrounding dam, filling phosphor, cutting, testing selecting, etc. Analysis the substrate circuit layer technological characteristics of surface morphology and element type between Ag paste printing coating and plating coating in SEM and EDS machine. It shows that it's worse in surface morphology and end face combination with Ag paste printing coating process circuit layer technology, and it appears delamination phenomenon in plating coating technology.3. Comparing the CSP's thermal resistance of two kinds coating technology on ceramic substrate circuit layer, and taking both thermal resistance compare with a thermal resistance of SMD, CSP's thermal resistance based on EMC substrate LED and new no substrate LED respectively. Finally concluding that the heat dissipation of CSP based on Ag paste of printing coating technology substrate is better than CSP based on the electroplating technology substrate, the thermal resistance of CSP LED based on ceramic substrates is less than SMD packaging LED, the thermal resistance of CSP LED based on ceramic substrates is less than CSP LED based on EMC substrate, and meanwhile, analyzing the causes of differences among them.4. Comparing the difference in optical properties between CSP LED based on a ceramic substrate with SMD packaging LED. Comparing difference between two kinds LED packaging respectively in surface brightness distribution, near field intensity distribution, spectrum area and color rendering index. Finally verified that the maximum Beam Angle and Half Angle of light intensity of CSP LED based on ceramic substrate is both bigger than SMD package LED. And meanwhile, analyze the reason that the overall luminous flux and color rendering index with SMD package LED greater than CSP LED in the condition of small power LED chip.