Detailed explanation of ceramic COB technology for LED packaging technology

The LED package is formed by a chip (Die) by a wire bonding, eutectic or flip chip packaging technology and a heat sink substrate Submount (sub-adhesive technology) to form an LED chip , and then the chip is fixed on the system board and connected into a light source mode. group.

At present, the LED packaging method can be roughly divided into a lens type (Lens-type) and a reflector type (Reflector-type), wherein the lens can be formed by molding or lens bonding; and the reflective cup chip is more. It has been formed by mixing, dispensing and packaging. In recent years, epitaxial, solid crystal and package design have gradually matured. The chip size and structure of LEDs have been miniaturized year by year. The power of high-power single chip is 1~3W, even more than 3W. LED power continues to increase, and the heat dissipation and heat resistance requirements for LED chip-mounted and system circuit boards are becoming increasingly stringent.

In view of the comprehensive considerations of insulation, pressure resistance, heat dissipation and heat resistance, ceramic substrates have become one of the important materials for chip adhesion technology. The technology can be divided into a thick film process (Thick film), a low temperature co-firing process (LTCC) and a thin film process (DPC). However, the thick film process and the low-temperature co-firing process use screen printing technology and high-temperature process sintering, which is prone to rough lines, inaccurate alignment, and shrinkage ratio problems, if the high-power LED products are increasingly finer for the line, or In the case of LED products that require accurate eutectic or flip chip processes, thick-film and low-temperature co-fired ceramic substrates are gradually in use.

To this end, the high heat dissipation coefficient thin film ceramic heat sink substrate is made of sputtering, electric/chemical deposition, and yellow light lithography. It has the characteristics of precise metal lines and stable material system. It is suitable for high power, small size and high brightness LEDs. The development trend has solved the stringent requirements for the resolution and accuracy of the metal substrate of the ceramic substrate in the eutectic/over-chip packaging process. When the LED chip uses ceramic as the carrier board, the heat dissipation bottleneck of the LED module is transferred to the system circuit board, and the heat energy is transmitted from the LED chip to the heat dissipation fin and the atmosphere, and as the function of the LED chip is gradually improved, the material is also improved. Gradually changed from FR4 to metal core printed circuit board (MCPCB), but with the development of high-power LEDs, the thermal coefficient of MCPCB material (2~4W/mk) cannot be used for higher power products. For this reason, ceramic circuits The demand for ceramic circuit boards has gradually become popular. In order to ensure material stability and light decay stability of LED products under high power operation, the trend of using ceramics as heat dissipation and metal wiring substrates has become increasingly clear. Ceramic materials currently cost more than MCPCB. Therefore, how to use the high heat dissipation coefficient of ceramics to save material use area to reduce production costs has become one of the important indicators for the development of ceramic LEDs. Therefore, in recent years, the integration of polycrystalline packages and system lines with ceramic material COB design has gradually attracted the attention of various packaging and system manufacturers.

COB is not a new technology in the electronics manufacturing industry. It means that the bare epitaxial wafer is directly attached to the circuit board, and the wire/solder wire is directly soldered to the gold-plated line of the PCB. (Wire bonding), through the sealing technology, effectively transfer the packaging steps in the IC manufacturing process to the board for direct assembly. In the LED industry, as modern technology products become more and more lightweight and high-capacity, in addition, in order to save the system board space problem of multiple LED chip design, in the demand of high-power LED system, it is developed to directly stick the chip. COB technology attached to the system board.

The advantages of COB are: high cost efficiency, simple circuit design, saving system board space, etc., but there are also technical thresholds for chip integration brightness, color temperature adjustment and system integration. Taking a 25W LED as an example, a traditional high-power 25W LED light source must be packaged into 25 LED components using 25 1W LED chips, while the COB package is to package 25 1W LED chips in a single chip. The secondary optical lens will be reduced from 25 to 1 piece, which will help to reduce the light source area, reduce material, and system cost, thereby simplifying the secondary optical design of the light source and saving assembly labor costs. In addition, the high-power COB package requires only a single high-power LED to replace multiple LED packages of 1 watt or more, which makes the product thinner and lighter.

At present, COB products are still mainly used in the production of COPCB products. However, MCPCB still has many problems of heat dissipation and excessive light source area, so the fundamental way is to update from the heat dissipation material to the most effective solution. The ceramic COB substrate has the following advantages: 1. The thin film process makes the basic line more precise, (2) the large amount reduces the cost, and (3) the plasticity is high, and can be designed according to different needs.

LED bulbs made by MCPCB substrate COB chip can not be dimmed, and LED dimmable bulbs assembled by ledaladdin with ceramic COB chips have been put on the market, with 5W, 6W, 7W, better performance, color temperature can be 2200K--- 8000K, lumens above 60LM/W.

The development of ceramic MCOB/COB is a trend to simplify the system board. The practical use of lighting fixtures, brightness, heat dissipation and cost control are all important factors.

A Battery Charger supplies current to the base plate. Once the AGV is in charging position and the collector has made contact with the base plate, the AGV computer turns on the current.

The base plate has chamfered entry/exit ramps to facilitate smooth drive-on/drive-off of the spring loaded collector. 

Battery charging stations may be installed anywhere within the system where the production process allows the AGV to stop (staging areas, turn arounds, loading stops etc.). 

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Xinxiang Taihang Jiaxin Electric Tech Co., Ltd ,

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