In the 1960s, scientific and technological workers used the principle of semiconductor PN junction light to develop LED light-emitting diodes. The LED developed at that time was made of GaASP, and its light-emitting color was red. After nearly 30 years of development, the LED, which everyone is very familiar with, can emit red, orange, yellow, green, blue and other colors. However, white LEDs for lighting have only been developed after 2000. This article introduces readers to white LEDs for lighting.
The first LED light source made using the principle of semiconductor P-N junction light emission came out in the early 1960s. The material used at that time was GaAsP, which emits red light (λp=650nm). When the driving current is 20 mA, the luminous flux is only a few thousandths of lumens, and the corresponding optical efficiency is about 0.1 lumens/W.
In the mid-1970s, the elements In and N were introduced to make the LED produce green light (λp=555nm), yellow light (λp=590nm) and orange light (λp=610nm), and the optical efficiency was increased to 1 lumens/watt.
In the early 1980s, GaAlAs LED light sources appeared, making the luminous efficacy of red LEDs reach 10 lumens/watt.
In the early 1990s, two new materials, GaAlInP, which emits red and yellow light, and GaInN, which emits green and blue light, were successfully developed, which greatly improved the optical efficiency of LEDs.
In 2000, the LED made by the former had a luminous efficiency of 100 lumens per watt in the red and orange zone (λp=615nm), while the LED made by the latter had a luminous efficiency of 50 lumens in the green zone (λp=530nm). /watt.
—1879 Edison invented the electric light;
—1938 Fluorescent lamp came out;
—In 1959, the halogen lamp came out;
—1961 High-pressure sodium lamp came out;
—1962 metal halide lamps;
—1969 The first LED light (red);
—1976 Green LED lights;
—1993 blue LED light;
—1999 white LED light;
—2000 LED is used in indoor lighting.
—The development of LED is the second revolution following the 120-year history of incandescent lighting.
-From the beginning of the 21st century, the LED developed through the wonderful encounter between nature, humans and science will become an innovation in the light world, a green technology light revolution that is indispensable for mankind.
—LED will start a huge light revolution after Edison invented the light bulb.
LED lighting is mainly high-power white LED single light. The world's top three LED lighting manufacturers have a three-year warranty, with large particles greater than or equal to 100 lumens per watt, and small particles greater than or equal to 110 lumens per watt. Large light decay particles are less than 3% per year, and small light decay particles are less than 3% per year.
LED solar street lights, LED flood lights, LED ceiling lights, and LED fluorescent lights are already available for mass production. For example, a 10-watt LED fluorescent lamp can replace a 40-watt ordinary fluorescent lamp or energy-saving lamp.
1. Energy saving: the energy consumption of white LED is only 1/10 of that of incandescent lamps and 1/4 of that of energy-saving lamps.
2. Longevity: The life span can reach more than 100,000 hours, which can be described as "one-time-for-all" for ordinary household lighting.
3. It can work at high speed: if the energy-saving lamp is frequently turned on or off, the filament will turn black and quickly break down, so it is safer.
4. Solid-state packaging, which belongs to the type of cold light source. So it is easy to transport and install, and can be installed in any miniature and enclosed equipment without fear of vibration.
5. LED technology is advancing with each passing day, its luminous efficiency is making amazing breakthroughs, and the price is constantly decreasing. The era of white LEDs entering the home is rapidly approaching.
6. Environmental protection, no harmful substances of mercury. The assembly parts of the LED bulb can be easily disassembled, and can be recycled by others without recycling by the manufacturer.
7. Light distribution technology expands the LED point light source into a surface light source, enlarges the light-emitting surface, eliminates glare, sublimates visual effects, and eliminates visual fatigue.
8. Integrated design of lens and lampshade. The lens has the functions of concentrating and protecting at the same time, avoiding the repeated waste of light and making the product more concise and beautiful.
9. High-power LED flat cluster packaging, and integrated design of radiator and lamp holder. It fully guarantees the LED heat dissipation requirements and service life, and fundamentally meets the arbitrary design of the structure and shape of the LED lamp, which has the distinctive characteristics of the LED lamp.
10. Significant energy saving. Using ultra-bright and high-power LED light source, with high-efficiency power supply, it can save more than 80% of electricity than traditional incandescent lamps, and the brightness is 10 times that of incandescent lamps under the same power.
11. Ultra-long life of more than 50,000 hours, which is more than 50 times that of traditional tungsten filament lamps. The LED adopts a highly reliable advanced packaging process-eutectic welding, which fully guarantees the long life of the LED.
12. No flicker. Pure DC work eliminates visual fatigue caused by traditional light source strobe.
13. Green and environmental protection. It does not contain lead, mercury and other polluting elements and does not pollute the environment.
14. Impact resistance, strong lightning resistance, no ultraviolet (UV) and infrared (IR) radiation. There is no filament and glass shell, there is no broken problem of traditional lamp tube, no harm to human body, no radiation.
15. Work under low thermal voltage, safe and reliable. Surface temperature≤60℃ (when ambient temperature Ta=25℃).
16. Wide voltage range, universal LED light. 85V~264VAC full voltage range and constant current, to ensure that the life and brightness are not affected by voltage fluctuations.
17. Using PWM constant current technology, high efficiency, low heat and high precision of constant current.
18. Reduce line loss and no pollution to the power grid. The power factor is ≥0.9, the harmonic distortion is ≤20%, and the EMI conforms to the global index, which reduces the power loss of the power supply line and avoids high-frequency interference and pollution to the power grid.
19. The universal standard lamp holder can directly replace the existing halogen lamp, incandescent lamp and fluorescent lamp.
20. The luminous visual efficiency rate can be as high as 80lm/w, a variety of LED lamp color temperatures are available, high color rendering index, and good color rendering.
Obviously, as long as the cost of LED lights decreases with the continuous improvement of LED technology. Energy-saving lamps and incandescent lamps will inevitably be replaced by LED lamps.
The country pays more and more attention to lighting energy saving and environmental protection issues, and has been vigorously promoting the use of LED lamps.
Post time: Jul-31-2021