LED lamps to replace high-pressure sodium lamp

Future LED lamp features:

Personal opinion, LED lamps to replace high-pressure sodium lamp, is a trend for future energy-saving emission reduction. LED lights to develop, I think it should be noted in the following areas:

1. To improve optical communication

2. Make things right for the second optical

3. Solve the heat

4. Modular

A. heat is the LED lights need to focus on resolving problems. As we all know, LED is an optoelectronic device, the course of their work only 15% to 25% of the energy converted into light, and the rest almost all the electricity converted into heat, so that LED's temperature. In high-power LED, the heat is a big problem. For example, a 10W white LED if its photoelectric conversion efficiency of 20%, there 8W of power converted into heat energy, if not increase cooling measures, the high-power LED of the device core temperature increase rapidly, when its junction temperature (TJ) rose by more than the maximum allowable temperature (typically 150 ℃), high-power LED will be damaged due to overheating. Therefore, in high-power LED lighting design, the design of the most important job is to thermal design. As for high brightness LED lamps, the use of the environment is harsh, if the heat are not properly solved, will quickly lead to LED aging, stability was reduced. Using a 250W high pressure sodium street lights, due to mature technology, thermal control, very good, even if the work of 5,000 hours, the light is still a very small decline. The current technology, under the same conditions of high-power LED street lamp, if the heat are not properly solved, the light will be an enormous decline. LED street lamp current cooling methods are: natural convection cooling, forced to install cooling fans, heat pipes, loop heat pipe cooling, and temperature and heat and so on board. Way to install the fan forced cooling system complexity, reliability, low temperature and panel heat pipe and cooling means higher costs.

B. LED lights will eventually choose modular installation and maintenance. The road is now the most widely used high-pressure sodium lamp, ballast and other components inside are not easy to damage, most are not bright because of light damage, maintenance of way as long as the light source can be replaced. Operation of a skilled workers can operate high-profile individuals. However, LED lights, a lot of internal components, in addition to light source (chip), other parts can lead to chip damage does not shine. Therefore, in the scene, could not immediately determine the causes of damage LED lights. If the LED lights are not bright, LED lights need to be shipped back to the factory off of the test. This LED lights to replace the way it is very cumbersome. The final version of the development of LED lights, is to develop a modular. Light source, electrical, etc. are all in accordance with the docking between the replacement, so that a skilled worker, but also fully capable of independently determine the causes of damage, and on-site maintenance.

C. luminous flux increase also need the extension from the high-power LED technology, chip technology and other infrastructure level, to further improve. At present, the domestic production of white LED approach is to first LED chip placed in the package substrate, with gold for bonding, and then YAG phosphor coating around the chip, and then epoxy encapsulated. Resin not only the protective role of the chip condenser also play a role. From the LED chip emits blue light hitting the phosphor layer around after numerous scattered reflection, absorption, finally sent to the outside. LED (blue) of the spectral lines of the peak at 465nm Department, the half-value width of 30nm. Sent part of the blue LED light to stimulate the yellow YAG phosphor layer, so that yellow light (peak 555nm), part of the blue light given out directly or after reflection, and ultimately achieving the external light shade for the blue-yellow 2, or white. Flip Chip Technology (FlipChip) can be compared with conventional LED chip packaging technology for more efficient out of light. However, if the chip is not in the bottom electrode light-emitting layer to increase the reflective layer reflecting light energy waste will result in the loss of about 8% of the light. So, bottom reflective layer material must be increased. Chips on the side of light must also be used to heat sink mirror reflection, to increase the rate of the device out the light. But also in flip-chip sapphire substrate (Sapphire) Light combined with epoxy resin should be added between the surface layer of silicone material to improve the chip out of the refractive index of light. After the improvement of optical packaging technology that can significantly improve high-power LED devices Idemitsu rate (flux).

D. LED lighting to optimize the design to improve the quality of LED use. Therefore, the Study of secondary optics with high-power LED light source designed to meet the large-scale cast light floodlight with light demand is particularly urgent. Through the second optical design technology, design plus a cup and multi-reflection optical lens and a light non-spherical surface, can improve the efficiency of the device to take light. Traditional light source direction of 360 °, most of reflector lamps rely on light reflection to a specific location, only 40% of the road just to reach directly through the glass, and the other just through the lamp reflector, and then projected out of the lamp , the efficiency of reflector lamps in general only 50% ~ 60%, so there are about 60% of the light output at the lamps inside, is the loss of 30% to 40% and then projected onto the road on. Light source a significant portion of light output is limited to the internal heat lamps consumed. LED lights are pre-shoot most of the light ray, can achieve "95% of the luminous efficiency, which is different from other LED light sources, one of the important features, if not a good use of this feature will make the advantages of LED large discount. Most high-power LED lights LED chip assembly because it is more, to light shine on so many different directions, we give full play to the overall chip package characteristics, the lens to be resolved, through the optical design, according to different needs, with different convex curves , relying on the light lens to be assigned to different directions to ensure that a large light angle can reach 120 ° ~ 160 °, a small light can be gathered in the 30 ° or less, lens, once finalized, in the production process guarantee under the premise of the same kinds of lamps distribution also reached a consensus on optical properties. Entirely through repeated trial-to constantly sum up experience, enabling LED street lamp road lighting standards to achieve the bat-wing light type. At present the tunnel lights, street lamps and general lighting applications have reached their respective places of lighting requirements.