High-power LED modules with ultra-high thermal conductivity

Since the development of LED lighting industry, white light lighting has not been able to effectively solve the problem of poor heat dissipation causing packaging material degradation and low luminous efficiency. The reasons include the heat dissipation path of LED packaging, the layers of barriers between LED packaging, PCB, and heat dissipation fins, and the upstream and downstream industries are working hard but do not understand each other, so it is difficult to integrate advantages and design high heat dissipation LED products. Guanghai Technology integrates LED packaging, PCB, and heat dissipation module into the same heat dissipation module with its excellent technology and design capabilities, and obtains the excellent results of 60W high-power LED module with Tj of 61.11℃.

Performance indicators of LED products

Luminous efficiency lm/w: The controlling factors of luminous efficiency are grain specifications, phosphor ratio, and heat dissipation rate.

Tjunction temperature control is life or light attenuation control: the grain itself has a high tolerance to thermal shock (the luminous efficiency decays by less than 1% for every 10°C increase in temperature). However, the effect of heat on all types of fluorescent materials is relatively sensitive. The light conversion efficiency of fluorescent materials decreases with increasing temperature (Figure 1), which also affects the life of fluorescent materials. In particular, when the temperature of fluorescent materials exceeds 70°C, they will decay rapidly. This means that the LED junction temperature (Junction Temperature, Tj) must be controlled below 70°C to effectively ensure the service life of the LED (generally, the life is calculated as L70, the time it takes for the LED to decay to 70% of its original brightness). As a basis for judging the life, it is generally required to be more than 20,000 hours.

Therefore, the ability to control Tj determines the luminous efficiency and life of the LED. Guanghai Technology has developed a technology that directly packages LED chips on a vapor chamber, achieving the following advantages.

The LED chip is directly packaged on the vapor chamber. There is only the thermal resistance of the bonding layer between the chip and the vapor chamber (Figure 3), rather than the layered thermal resistance structure of the traditional module (Figure 4).

The thermal conductivity of the temperature vapor chamber is at least 800W/mK, which is twice that of pure copper (400W/mK), four times that of aluminum nitride substrate (230W/mK), and 260 times that of aluminum substrate (MCPCB) (3W/mK), thus achieving excellent thermal conductivity.

The measured Tj of the 60W high-power LED module is 61.11℃ (Figure 6), which is the lowest Tj measured in the industry.

Easy to control: For Guanghai Technology's LED modules, since there is only one bonding layer between the vapor chamber and the chip, the temperature of the vapor chamber is almost equal to Tj. Therefore, Tj can be easily controlled by controlling the area of ​​the heat sink fins, and controlling Tj is equivalent to controlling the life of the LED.

Low cost: This high-power module does not have the stacked structure of previous LED modules. It directly bonds the LED chip to the temperature equalization board, and the intermediate process materials are omitted. Therefore, its cost is the most competitive model.

The technology developed by its excellent design capabilities to directly package LED chips on the temperature equalizing board has completely solved the problem of poor heat dissipation of high-power LED modules and opened up a new path for high-power LED modules.