LED lighting systems and future trends in the current profile
People are used to look at things under the sun, for general lighting, the needs of the people close to the sun is mainly the quality of light, so white LED semiconductor lighting technology is an important indicator. LED compact light-weight, low driving voltage, full-color, long life, high efficiency, resistance to vibration, easy to control light and other features designed for different places and for the purpose of the lighting system provides excellent conditions. As the single LED power is small, light intensity is low, should not be used alone, this number must be designed to be practical LED assembly with LED lighting system. But the white LED general lighting requirements and there is a certain distance, there are still many technical and cost issues need to be resolved.
Semiconductor lighting system"s main technical overview
Lighting system thermal management
General is often described as cold LED light source, this is because the LED light through the composite theory of electronic photon is sent directly without the need to heat the process. However, due to the presence of Joule heating, LED light, while the heat is also accompanied by, and for high-power LED applications and a number of occasions, calories add up and can not be underestimated, LED unlike incandescent, fluorescent and other traditional lighting sources, high temperature will shorten or even end their life. And the LED is temperature sensitive device, when the temperature rises, a sharp decline in its efficiency, so the cooling system design and application of LED technology development is required to face. As the forced air cooling is usually not desirable in the light, so with the input power increases, heat sinks and other methods to enhance natural convection cooling in the design of LED lamps and light sources play an increasingly important role.
Improve the color
The current widespread use of white LED superimposed by a blue LED to emit blue light yellow light to stimulate the yttrium aluminum garnet (YAG) phosphor, the synthesis of white light. Because of its light spectrum contains only blue, yellow two spectra, so there is high color temperature, color rendering index of the problem of low, does not meet the general lighting requirements. The sensitivity of human eye color sensitivity much higher than the light intensity of illumination, the light source color is often more important than the luminous efficiency. So adding an appropriate amount of red phosphor and to maintain a high luminous efficiency white LED lighting is an important issue.
The second optical lighting system design
Traditional incandescent lamps with a long, fluorescent light fixtures for the reference to determine the shape of the optical and the standard, the LED lighting system should be considered instead of the traditional lamps with LED light module assembly methods, give full consideration to its optical properties, specifically for the LED light source design of different lamps. Optical system design mainly includes the following aspects: ① According to lighting objects, flux requirements, determine the shape of the optical system, LED number and size of power; ② the number of combination LED light tubes designed light source, ring light, or surface light source of the "secondary source", according to form the second light source, computing illumination optical system; ③ illumination optical system constituted a "secondary source" of each LED tube light distribution control is very important.
Because the LED beam focus, easier to control, and does not require concentrating reflector, helps to reduce the depth of the lamp. For example, the use of plane mirror optical system, can use only 1 or 2 LED can illuminate a large surface, and the depth of a thin lamp; The use of optical technology, LED light tube directly mounted on the side, can greatly reduce the light source and other groups volume occupied by pieces, made of thin lamps.
Improve system reliability
LED light source lamp longevity have called it that, as a solid light-emitting device, the theoretical life of 100,000 hours or more, its life is longer than traditional light sources, it is not easy to replace in some occasions to maintain, maintenance costs can be greatly reduced . But now many applications can not see the advantage, but to the user to see the light of serious decline, and short life, there is less than one million hours with the bad, because everyone is using the LED electronics industry the most commonly used indicator of Ф3 ~ Ф5mmLED, the use of simple electronic circuits to increase the current to increase its luminous intensity, but the LED only get a brief high-intensity, but should lose the life of the LED. Therefore, carefully choose the design of semiconductor lighting LED, power LED should be used as a lighting source.
Improve flux, lower prices
Currently a single 1W LED devices, luminous flux of about 25lm, good quality price to more than $ 5, some have $ 3 difference. The 25lm flux for general lighting purposes is too small, an ordinary incandescent lamp 60W luminous flux greater than 700lm, that is, to replace traditional lighting require multiple LED devices, plus the drive circuit, lamp shells, lamp, etc., such a high cost of white LED lighting in general the biggest problem. In particular, efficiency is currently 25 ~ 45lm / W, need to be further improved.
Power supply, integrated circuit and the lamp
Design for LED lamps, incandescent and fluorescent lamps need to pay attention to designers rarely an issue of concern is the power supply. Most incandescent light directly from the AC power cord, so no power supply. Fluorescent lamp ballasts used to complete the power function. However, the need for specialized power and LED driver circuit and its facilities, the design should be considered when the lamp power and lighting systems. Semiconductor lighting and solar power are the most important feature of environmental protection, energy saving, long life and safety. Solar power and semiconductor lighting combine to complete the electro-optic photoelectric conversion, is the best combination. To solar power as the power of nature can take advantage of the independent semiconductor-based lighting, energy saving, environmental protection, long life, but also eliminates the need for wires and associated facilities, has a huge market space.
LED lighting technology trends
1, abandoning the traditional lighting LED lamps only added LED light module design method to fully consider the LED optical properties, development of dedicated LED lamps.
2, power supply and control circuit design, power side to change the current widespread use of blood pressure and impedance voltage divider capacitors are applied to design a reasonably small constant current source circuit, the drive current in a clock cycle modulation to improve LED lamps stability, while further improving power efficiency.
3, the control circuit in circuit design, to the centralized control, standard modular, scalable system development in three areas.
4 LED light in the current efficiency and luminous flux limited circumstances, give full play to the diversity of LED colors, the development of LED lighting color control circuit.
5, to play the advantages of LED, the development of LED lighting and lighting systems with PV systems.
6, the development of solar energy and high brightness LED integrated technology solutions and LED lighting, solar system and control system to match.
7, the development of integrated flat panel for indoor lighting, lighting systems, LED lighting trend is integrated with the building.
8, the development of LED lighting simulation system, to accelerate product development.
[This information has already been had a
look around 2270
times!]
