Domestically invested unmanned driving can realize intelligent voice, do not need to enter the address, can automatically locate to reach the place, see someone in front of the automatic pause;  You can also customize the scene you want according to your needs, such as seat adjustment, personalized large screen, and so on. You want a "romantic star" will immediately present such screen page.  In fact, the drone uses lidar, or laser sensors.  Today we will talk about the application value of aluminum nitride ceramic substrate in unmanned laser sensor.  

1, what is a laser sensor  

       Lidar, lidar is a combination of laser global positioning System (GPS) and inertial navigation system (INS) technology in one system, using dry data and generate accurate digital models.  The combination of these three technologies enables highly accurate location of the spot of light that a laser beam strikes on an object.  In short, it is a sensor that uses laser beam to detect the target's position, speed and other characteristics.  

2, laser sensor characteristics and application products  

         Lidar has high resolution, good hiding, strong anti-interference ability, good low-altitude detection performance, small size and light weight.  Advantages, the main reason is on the laser, might say GPS everyone not unfamiliar, but laser may be unknown, laser can be divided into gas laser dye laser, solid laser semiconductor laser with semiconductor laser is one of the most widely used, at present most of the laser radar is used in the semiconductor laser.  

3. Why do laser sensors use aluminum nitride ceramic substrate?  

         In general, the wavelength of the semiconductor laser is 0.2-0.3nm/℃, which increases the spectral width and affects the brightness of the color.  In addition, when the forward current flows through the PN junction, the thermal loss of the junction area produces a temperature rise, near room temperature, the temperature rises 1℃, the semiconductor laser luminous intensity will reduce 1% or so, maintain color purity and luminous intensity is very important, in the past to reduce the driving current method, reduce the junction temperature,  Most of the semiconductor laser drive current is limited to about 20mA, but the semiconductor laser light output will increase with the increase of current, many power semiconductor laser drive current can reach 70mA, 100mA to 1A level, need to improve the packaging structure to ensure the life of the laser,  The new semiconductor laser packaging design concept adopts low thermal resistance packaging structure and technology to improve the thermal characteristics.  For example, the use of large area chip flip structure, the use of silver glue with good thermal conductivity, the alumina support is replaced by aluminum nitride support, solder bump silicon carrier directly installed in aluminum nitride ceramic heat sink and some other methods.  But it's all tied to the alN ceramic substrate.  

Aluminum nitride ceramic substrate thermal conductivity by laser sensor preferred aluminum nitride ceramic plate thermal conductivity in 170W/(M · K ~260W/(M · K), alumina ceramic substrate thermal conductivity is 30W/(MK) or so, heat dissipation is better than ordinary metal substrate, coupled with ceramic substrate insulation performance is relatively good, high temperature and high pressure resistance, thermal expansion coefficient is small,  Mainly because of the barrier of an insulating layer, the silicon carrier can not directly contact the substrate, so the aluminum nitride ceramic substrate is a good match.  

Semiconductor laser has been widely used in laser ranging, laser radar, laser communication, laser simulation weapons, laser warning, laser guidance, tracking, initiation, automatic control and detection instruments, and has formed a wide market.  Semiconductor laser is a mature early, rapid progress of laser, because of its wide wavelength range, simple production, low cost, easy to mass production, and due to the small volume, light weight, long service life, therefore, varieties of fast development, application range, has more than 300 kinds of semiconductor laser is the most important application field of Gb LAN and semiconductor laser.  The semiconductor laser with the wavelength of 1300nm-1550nm is suitable for 10Gb LAN system. The application of semiconductor laser covers the whole field of optoelectronics and has become the core technology of optoelectronics science.  

Due to the epidemic and the sino-US trade war, the development of semiconductor chips in China has been affected to a certain extent. At the same time, it is also a kind of luck. The country continues to increase investment and support for semiconductors, and we believe that we can achieve most of self-sufficiency in the future.