High power LED heat dissipation new breakthroughs in ceramic COB technology greatly save the packaging cost
LED encapsulation mode on grain ( 死) After a dozen lines, eutectic or flip chip packaging technology and its heat dissipation substrate Submount ( Adhesive technology) Link to the LED chip, and then fix the chips on the system board link into a light source module. At present, the LED packaging methods can be roughly divided into the lens type ( 镜头- - - - - - 类型) And reflection cup type ( 反射器, 类型) In which the lens shape can be molded ( 成型) Or bonded molding lens; As shown in figure 1 ( 一) Shown, while reflection cup type chip consists of rubber mixing, more 賿, encapsulation molding; As shown in figure 1 ( b） Shown below.
in recent years of epitaxial, solid crystal and packaging design is gradually mature, grain size and structure of the LED miniaturization year by year, high power single grain power up to 1 ~ 3 w, even more than 3 w, when the LED power, LED grain for load and system circuit of edition of cooling and heat resistance requirements, it has become increasingly harsh. Given insulation, pressure, heat dissipation and heat comprehensive consideration, such as ceramic substrate become grain to one of the important material of adhesive technology. The technology can be divided into the thick film process ( 厚膜) , low-temperature firing range ( 确立) With thin film process ( DPC） Methods such as made. However, thick film process and low-temperature firing process, is the use of screen printing technology and the high temperature process of sintering, rough, registration is not accurate, easy generation lines and shrinkage ratio, if in view of the high power LED product line more refined, or require registration accurate eutectic or flip chip process in the production of LED products, thick film and low temperature co-firing ceramic substrates, gradually don't apply to use. Therefore, high coefficient of heat transfer film radiating ceramic substrate, using the coating, electric/chemical deposition, as well as Huang Guangwei shadow process and become, have the metal line is precise and stable material system features, suitable for high power, small size, high brightness LED the trend of development, but also solves the eutectic/flip chip packaging process for ceramic substrate metal line resolution and accuracy of the stringent requirements. Thin film ceramic COB ( 板上芯片) Heat dissipation substrate can conform to different lighting needs.
when LED grain ceramic as loading board, the LED module of heat dissipation is transferred to bottleneck system circuit board, it will transmit the heat from the LED chip to the cooling fins and the atmosphere, as LED grain function gradually enhanced, material is also gradually from FR4 shift to metal core printed substrate ( MCPCB) , but as of the demand on high power LED, MCPCB shading coefficient of heat transfer ( 2~4W/mk） Cannot be used for higher power products, therefore, ceramic circuit board ( 陶瓷电路板) The demand of growing popularity. In order to ensure the operation in the high power LED products under the material failure stability, stability and light with ceramic as the heat dissipation and the trend of metal wiring substrate has become clearer. The ceramic material cost is higher than the MCPCB and thus, how to make use of ceramic high coefficient of heat transfer characteristics, save material use area to reduce production costs, become the important index of ceramic LED development. Therefore, in recent years, in order to design integration of polycrystalline ceramics COB encapsulation and system lines also gradually by the encapsulation and system manufacturers.
COB is not a new technology in the electronic manufacturing industry, is refers to the bare wafer paste directly to the circuit board, and the wire/welding wire welding on the PCB gold-plated line directly, also commonly known as the line, 线焊接) , and then through the technology of sealing glue, effective packages in the IC manufacturing process steps on the circuit board assembly directly. In LED industry, the products of modern science and technology is more and more pay attention to light and high portability, in addition, in order to save more than LED chip design, system board space problem, in the high power LED system requirements, and develop the grain paste directly on the system board of COB technology.
COB advantage: high cost efficiency, simple circuit design, system board space saving, but also there is a grain integration of brightness, color temperature and threshold and system integration technology. 25 w LED, for example, the traditional high power of 25 w LED light source, the 25 of the 1 w leds should be used in chip packaging into 25 LED components, and COB packaging is 25 of the 1 w LED chips encapsulation in a single chip, thus requiring secondary optical lens will be from 25 piece cut to 1 piece, help narrow light source area, cut materials, system cost, thus simplifies the light source is the secondary optical design and save the assembly labor costs.
in addition, high power and only single high power LED COB packaging to replace more than 1 watt, ) The above LED encapsulation, make product volume is more thin and short. Currently on the market, the production of COB products still give priority to in order to use the MCPCB substrate, MCPCB, however there are still many heat and light source area is too big problems must be solved, so the path to the root, or from the heat dissipation material updated to the most effective solution.
ceramic COB base board has the following advantages: 1. Thin film process, let basically the line more accurate; （ 2) Large amount of cost reduction; （ 3) High plasticity, can be in accordance with the needs of partners.
the development of the COB is to simplify the trend of the system board, lighting the practical application, the brightness of lamps and lanterns, heat dissipation, and cost control, the key factors that are important. ICP in addition to providing all kinds of film cooling substrate to single chip encapsulation, more provides independent development of thin film circuit COB substrate, high power to different purpose of users, with its more flexible choice, to expect LED lighting will become more accepted, for earth as a green heart.