Street lights and led street lamp intelligent dimming system have what use?

Intelligent dimming system flexibly adjust light output to reduce the energy consumption of the traditional high pressure sodium lamp, can achieve the dimming control of a small scale, such as closing a side or interval closed street lamp, inevitably bring change in the form of lighting, easy to cause potential safety hazard. LED street light,

intelligent dimming system flexible adjustment light output to reduce the energy consumption of the

traditional high pressure sodium lamp, can achieve the dimming control of a small scale, such as closing a side or interval closed street lamp, inevitably bring change in the form of lighting, easy to cause potential safety hazard. LED street light 0 - can be realized 100% continuous adjustable light, can be adjusted according to the environmental light and traffic light output, to guarantee the quality of the lighting at the same time reduce unnecessary power consumption. Development of semiconductor lighting system of zhongshan university research center of the LED street lamp intelligent dimming system can easily control the working state of the LED, and by changing the drive current to control the brightness. In later into the wee hours, for example, by reducing the whole lamp current or close the interior of the lamps and lanterns of LED light emitting component to achieve low power operation, to achieve the effect of energy saving.

semiconductor lighting system of zhongshan university research center also control the Zigbee wireless communication technology application on the LED street light system. Zigbee wireless control system of the starting point is hoping to develop a low-cost wireless networks are easily, with a simple protocol stack is compact, save electricity, reliable characteristics such as large capacity, short time delay, network ( Figure 3) 。 Zigbee transceiver module integrated in every LED street lamps, and by way of relay, put all the information collected on the terminal, so as to realize the terminal to the operating condition of each LED street lamp for effective monitoring, the function of control system, troubleshooting and guard against theft. Thermal

optimize cooling and thermal management control system

LED under the forward voltage, overcome p - driven by electron in an electric field N n junction of the electric field at transition to p area with p and cavitation occurs inside the compound. Due to the transition to the free electrons is higher than that of p p area area of valence electrons energy, electronic back to lower energy state for the compound, excess energy release in the form of photons, the light of the radiation out only after the chip itself and encapsulating semiconductor media medium to reach the outside world.

considering current injection efficiency, radiation light quantum efficiency, external factors such as light extraction efficiency and the chip for 100 lm/W leds only about 30% of the electric energy into light energy, and the rest of the energy is converted into heat energy, the temperature rise of the LED chip. For the LED chip, if the quantity of heat cannot effectively out, can lead to raise the temperature of the chip, the thermal stress caused by non-uniform distribution, chip light-emitting efficiency and phosphor efficiency decline.

with p - N junction temperature rise, the emission wavelength of LED chips red shift will occur, resulting in a decline in YAG phosphors excitation efficiency and the total luminous intensity is reduced, the white light chroma drift. When the temperature exceeds a certain value, the failure rate of the device will be rising exponential law. Device temperature rising every 2 ℃, reliability will decline by 10%. In order to guarantee the life of the device, p - general requirements N junction of junction temperature under 90 ℃. When multiple leds dense array or integrated packaging system heat dissipation problem is more serious. Therefore solve the problem of heat dissipation has become a precondition for LED lights.

how to improve the LED street lamp cooling ability is the core issue of LED encapsulation and LED street lamp design. LED street light heat dissipation problem into p - chip N junction to the epitaxial layer; Epitaxial layer to the packaging substrate; Packaging substrate into three layers from the outside environment. The three links constitute the heat conduction channel. For heat dissipation problem of LED, semiconductor lighting system of zhongshan university research center, respectively, the following all aspects of optimization design was carried out on the heat dissipation and thermal management systems.

p - chip N junction to the epitaxial layer cooling: in the process of the growth of gallium nitride materials, improve the material structure, optimizing the growth parameters, the extension of access to quality, improve the device internal quantum efficiency, radically reduce the generation of heat, to speed up the p - chip N junction to heat conduction of the epitaxial layer.

epitaxial layer to encapsulate the substrate heat: on the chip packaging, by using the flip chip structure, eutectic solder packages ( Figure 4) , metal structure of circuit board. On the device packaging, select the appropriate substrate material, such as metal printed circuit board ( MC - PCB） , ceramics, composite metal substrates such as thermal conductive performance good packaging substrate, to accelerate heat from escaping through the epitaxial layer to encapsulate substrate.

packaging substrate to the external environment of the heat dissipation: the LED street lamp is generally the high-power white LED array by means of reflow soldering welding on the metal substrate, and then install the metal substrate closely in bulk on the heat dissipation fin of aluminum, copper materials. The heat generated by the high power white LED by metal substrate is passed on to the heat dissipation fin, the use of natural convection or artificial forced convection cooling way to achieve.

semiconductor lighting system of zhongshan university research center for high-power integrated packaging heat large, concentrated light source module, the characteristics of high-power integrated encapsulation light source module is installed on the mean temperature plate, using the mean temperature plate fast diffusion heat performance of LED the heat generated by the rapid lateral diffusion; Also USES the heat pipe in heat dissipation fin part ( Straight type of loop heat pipe and pulse heat pipe and heat pipe) To reduce the strengthening heat transfer and reduce the thermal resistance ( FIG. 5) ； In the cavity of the LED street lamp to produce artificial forced convection way to strengthen the convection.