The light source adopts a modular design scheme to achi […]
The light source adopts a modular design scheme to achieve the best match between ground illumination and power. By increasing or decreasing the number of light sources, it can meet different road width and illumination requirements, and achieve the purpose of satisfying the lighting requirements of the city without wasting power.
LED street lights should be developed and should be noted in the following aspects:
A. The improvement of optical communication needs to be further improved from the basic level of high-power LED epitaxial technology and chip technology. The method for making white LEDs at home and abroad is to place the LED chips on the package substrate, bond them with gold wires, and then apply YAG phosphor powder around the chip, and then encapsulate with epoxy resin. The resin acts both as a protective chip and as a concentrating mirror. The blue light emitted from the LED chip is reflected and absorbed by the scattered phosphor layer in the surrounding phosphor layer, and finally emitted to the outside. The peak of the spectral line of the LED (blue) is at 465 nm and the half value width is 30 nm. A part of the blue light emitted by the LED excites the yellow YAG phosphor layer to emit yellow light (peak value is 555 nm), and a part of the blue light is directly or reflected and then emitted outward, and finally the external light is blue-yellow light, that is, white light. FlipChip can get more effective light output than traditional LED chip packaging technology. However, if a reflective layer is not added under the electrodes of the light-emitting layer of the chip to reflect the wasted light energy, about 8% of the light is lost. Therefore, a reflective layer must be added to the substrate material. The light on the side of the chip must also be reflected by the mirror surface of the heat sink to increase the light extraction rate of the device. Moreover, a layer of silica material should be added between the sapphire substrate of the flip chip and the light-guide bonding surface of the epoxy resin to improve the refractive index of the chip. Through the improvement of optical packaging technology, the light extraction rate (light flux) of high-power LED devices can be greatly improved.