Heat dissipation method of semiconductor laser welding machine
Semiconductor laser welding machine is a kind of laser equipment commonly used in electronic products and other industries. It uses the excellent directivity and high power density of semiconductor laser beam to weld. The principle is to focus the laser beam in a small area through the optical system, so as to form a heat source area with high energy concentration at the welded place in a very short time, so as to melt the welded object and form solid solder joints and welds.
As the main part of semiconductor laser welding machine, semiconductor laser is one of the most used optoelectronic devices so far. With the continuous progress of technology and the improvement of mass production ability of devices, it can now be applied to more fields. Semiconductor laser is a kind of laser that mainly uses semiconductor materials as working materials. Because of the different material structure, the laser will be different. Semiconductor lasers are characterized by small volume and long service life. In addition to the field of communication, they can also be used in radar, sound measurement and medical treatment.
Due to the large light output power of a single chip and the large heat generated per unit area, if the heat dissipation technology is not done well, the chip is easy to die and the performance will decline rapidly.
The heat dissipation mechanism of semiconductor laser packaging is mainly composed of laser chip, welding layer, heat sink, metal layer, etc. The welding layer in the heat dissipation structure of semiconductor laser mainly connects the chip and heat sink by welding. When high-power semiconductor lasers are used, in order to reduce the thermal resistance, some materials with high thermal conductivity are often used during welding to form good heat dissipation of semiconductor lasers and prolong the service life of lasers.
At present, the main heat dissipation methods of lasers are divided into traditional heat dissipation methods and new heat dissipation methods. The traditional heat dissipation methods include: air cooling heat dissipation, semiconductor cooling heat dissipation, natural convection heat dissipation, etc. the new heat dissipation methods include: flip heat dissipation and microchannel heat dissipation.
Large channel liquid cooling :
During the research, researchers found that the heat dissipation effect of the spoiler structure will be better than the traditional cavity structure, but the pressure will also increase in the channel. It is found that although large channels are widely used, due to the continuous improvement of laser output power, large channel water cooling and heat dissipation can not meet the heat dissipation requirements of high-power semiconductor lasers.
Natural convection cooling:
Natural convection heat dissipation is to use some materials with high thermal conductivity to take away the heat generated, and then dissipate heat through natural convection. During the research, scientists also found that fins can also help heat dissipation, and can maximize the heat transfer rate in the heat dissipation system. When the temperature is the same, the fin spacing will decrease with the increase of fin height.
Semiconductor cooling:
The main characteristics of semiconductor refrigeration and heat dissipation methods are small volume and strong reliability. Semiconductor refrigeration and heat dissipation methods often appear in high-power semiconductor lasers. Because Tec refrigeration is added, the size of the package is increased accordingly, and the cost of the package is also increased accordingly. When in use, the cold end and heat sink of the semiconductor chip are connected together, and the hot end is dissipated through convection and TEC's own heat.
