Thermal management of wearable devices such as VR/AR
Consumer electronics refer to electronic products designed around consumer applications that are closely related to life, work, and entertainment. The emergence of consumer electronic products is a huge transformation in daily life, which greatly improves the convenience and quality of life of consumers and becomes an indispensable component of their daily lives.
Based on the iterative development of consumer electronics manufacturing technology and the popularization of mobile internet applications, the user base of consumer electronics products continues to expand. Currently, although the traditional consumer electronics device market represented by smartphones, tablets, and laptops is becoming increasingly saturated and growing at a slower pace, as an emerging branch of consumer electronics, intelligent wearable electronic products represented by VR/AR are still continuously developing.
The overall industrial chain structure of intelligent wearable products and consumer electronics is basically consistent: upstream is the production of raw materials and components; Midstream manufacturers; Downstream are wearable devices. Among them, the manufacturing of midstream structural components and the production of downstream optical modules are the key to intelligent wearable products, with high technological content and significant capital investment. At the same time, they are also the most fiercely competitive and high-risk areas in international competition. At the same time, with the continuous development of intelligent wearable products, higher requirements have been put forward for the heat dissipation performance of structural components.
According to different working principles, thermal management materials can be divided into two types: active (active) and passive (passive). Active cooling components generally use the principle of thermal convection to forcibly dissipate heat from heating devices, such as fans, liauid pumps in liquid cooling, and compressors in phase change refrigeration. The characteristic of active cooling heatsink components is high efficiency, but it requires the assistance of other energy sources. Passive heat dissipation generally adopts the principle of heat conduction or radiation, mainly relying on heating elements or fins for cooling. Thin and lightweight consumer electronics such as mobile terminals and tablets are generally adopted due to internal spatial limitations. The passive heat dissipation method includes graphite heat dissipation film, graphene film, heat pipe, and soaking plate. To effectively conduct heat, the use of thermal interface materials between heating and cooling devices is often required, such as metal brazing layers, thermal conductive silicone, thermal conductive paste, etc.
In practical application scenarios, thermal management materials and devices often need to be combined for use. Taking IGBT power devices widely used in new energy vehicles as an example, the heat transfer path of the chip to the outside includes the chip welding layer (metal), DCB/AMB ceramic circuit board layer (including ceramic substrate layer and copper coating layer), system welding layer (metal), metal substrate, interface material (thermal conductive silicone grease), and heat sink. Finally, the heat sink and air conduct convective and radiative heat transfer, and there is thermal resistance throughout the entire conduction process, Thermal resistance is the main factor affecting the heat dissipation of IGBT power modules.
To enhance the heat dissipation effect, reducing thermal resistance is the most important method. With the continuous improvement of chip performance, device miniaturization, and lightweight requirements, the industry's requirements for thermal management design are also constantly increasing. Thermal management researchers need to flexibly apply active passive thermal management methods, as well as arrange and combine substrates, heat sinks, and interface thermal materials. For example, IGBT modules can be combined with soaking plates, thermoelectric modules, and even liquid cooling modules to achieve better heat dissipation.
