Study On Ceramic Core Printed Circuit Board For Power LED

High power white-light LED (Lighting Emitting Diode) used for illumination is fast replacing incandescent and fluorescent lighting owing to its energy saving, long-life, pollution-free advantages. However, with rising power output, it has grown increasingly necessary to shed excess heat to maintain reliability, so more complex packages have been adapted for efficient heat dissipation. Ceramic matrix printed circuit board has the advantages of good heat-conducting performance, electric insulation performance and mechanical processing performance etc, thus being suitable for use in high power light emitting diode (LED) package. From the aspects of theory, experiment and industrialization, this paper studied the high power LED with high thermal conductivity using ceramic matrix printed circuit board. The main research work and achievements as follows:1. Having established the circuit heat-dissipating model of the high power LED, and studied the influence of thermal conductivity of different materials and the thickness of base plate on the performance of the heat dispersion. ANSYS finite element steady-state thermal analyses have been used for simulating the heat-dissipating model, and the ideal device materials and structure of high power LED were presented and validated by experiments. The experimental results show that the new ceramic substrates can make the thermal resistance of high power LED decreases to 10 K/W compared with the 300 K/W of the traditional FR-4 epoxy resin copper clad. The proper thickness of Ceramic substrates can make the radiating efficiency and material tenacity of substrates reach the best value.2. Putting forward a complete preparation solution for heat dissipation of printed circuit preparation using alumina ceramic substrate. Choosing the alumina ceramics which has the mature processing technology on market as substrate materials, what' more, using the screen printing technology and positive inks- masking and negative inks-masking method to prepare circuit design, and finally, we obtained the printed circuit board of high power LED successfully which could fulfill with the requirements of the industrialization. The solution combined the existed preparation process of printed circuit, and greatly reduced the cost of the new process.3. Designing the multi-layer conductive structure "transition layer & barrier layer & weld layer". The samples have been tested, the pull-off strength of the prepared conductive layer film reaches more than 1.5 MPa, and can withstand the dissolution of 450℃lead-free solder, which meets the process requirements of lead-free SMD soldering.4. Involved in the design and working out production line of magnetron sputtering and the establishment of sputtering technology, debugged the equipment and studied its industrial production.5. Explored preparation method of the using AlN as insulating layer in MCPCB, prepared insulation layer on aluminum matrix plate by plasma spraying, analyzed and proposed methods for preparing conductive circuits in this insulation layer.