What is the trend of LED lights in the future
The application of the LED lamp is unparalleled with the other lamps of the LED lamp. The LED lamp is developing at a very fast speed and gradually replacing other lamps and lanterns. Now the LED lamp has been widely used in the various lighting fields.
1. high power LED technology. LED has the problems of electrostatic emission damage, thermal expansion coefficient and other performance bottlenecks and heat dissipation, so that its power can not be very large, low brightness. At present, the high-power LED chips with stable performance are 1W and 3W. LED power can be improved by integrated chips, but the current technology is not mature, mainly need to solve the problem of heat dissipation. High-power LED lamps can also be realized by series, parallel or parallel connection of multi-bead LEDs. The latter two low efficiency, less use, multi-bead LED series is the mainstream of LED lighting applications. But a single bead has a fatal weakness in series, and a damaged road will not work. This is a major bottleneck restricting the application of high-power LED lamps in the field of lighting. To increase the power of LED lamps, one is to increase the power from the chip, the other is to optimize the circuit design and improve the power.
2. heat dissipation technology. Temperature is an important factor affecting the LED. The increase of temperature will accelerate the light attenuation of LED, and the temperature of the chip node directly affects the life of LED, so the power of LED is limited by the power of LED.
The internal heat of LED is mainly produced by LED chip and printed circuit board. For small power LED, heat can be sent out by natural conduction convection, but many aspects of heat dissipation should be considered for high power LED. In terms of heat dissipation design, it is usually considered from the aspects of LED packaging cooling, circuit board cooling and increasing heat dissipation parts.
3. chip technology and chip packaging technology. The key to the development of chip technology is the selection of substrate materials and the growth technology of epitaxial films. The key to the improvement of technology is to reduce the density of defects and how to develop more efficient and stable devices, and how to improve the efficiency of the LED chip is the most important measure of the current overall technical indicators. The traditional substrate materials include sapphire, Si and SiC. Currently popular materials include ZnO, GaN and so on. The main method of manufacturing epitaxial wafers is metalorganic chemical vapor deposition. According to the 2011 LED global online report, a new gallium nitride growth process has been proposed by the University of North Carolina in the United States. This new process is expected to reduce the defects of the material by 1/1000 to produce a higher luminance of the LED luminescent two grade tube.
4. optical design technology. LED is a point source and has a good direction. Through the design of LED lattice, the design of lens and reflector, two optical designs and even three optical designs, the ideal light distribution curve can be achieved. It is also the difficult point of optical design. In the overall lighting, the lamp needs to have larger illuminating surface. It can use linear LED light strip and light guide plate technology to make it a surface light source. The LED automobile signal lamp can be composed of a reflector and a light distribution mirror, and the light shape distribution can be achieved by reasonable design.
5. drive technology. LED constant current drive is usually driven by two kinds of LED, inductance type and switched capacitor type. The inductor LED drive has high driving current and low end voltage of LED. It is suitable for driving many LED applications. Capacitive LED driver is commonly used in high-power LED lamps. The LED terminal voltage and current are high, and high power and luminous efficiency can be obtained. The design of the LED drive circuit may be complex according to the specific needs, but in the design of the circuit, it is necessary to take into account the high reliability of the power supply and the various factors such as the surge protection.