LED light source lighting technology and its application in traditional lighting environment

An important step in realizing this plan is to develop and promote efficient and energy-saving lighting appliances, saving electricity, reducing environment and light pollution, the establishment of a high efficient, comfortable, safe and reliable, economic and environmentally friendly lighting system. The application of LED light source in the field of lighting is the product of the rapid development of semiconductor light-emitting materials technology and the concept of "green lighting". "Green lighting" is a new concept in the field of foreign lighting in the late 80s of last century, the implementation of China's "green lighting project" began in 1996. An important step in realizing this plan is to develop and promote efficient and energy-saving lighting appliances, saving electricity, reducing environment and light pollution, the establishment of a high efficient, comfortable, safe and reliable, economic and environmentally friendly lighting system.

A, LED lighting concept

LED (Lighy Emitting Diode), also known as light-emitting diodes, they use solid semiconductor chip as luminescent materials, when the two ends with forward voltage, carrier in semiconductor composite, release of excess energy caused by photon emission of visible light.

(a) the development history of LED

The application of P - N first light source semiconductor principle LED introduced in early 1960s 1964, the first red light emitting diode, after the Yellow LED. Until 1994, blue, green LED was developed successfully. In 1996 by the Japanese company Nichia (Nichia) successfully developed a white LED.

The LED of its inherent characteristics, such as energy saving, long service life, vibration resistance, fast response characteristics, widely used in the cold light source, indicator lights display, landscape lighting and other fields, everywhere in our daily life, household appliances, telephone, dashboard lighting, automotive anti fog, traffic signal lamp. However, due to its poor brightness, high price and other conditions, can not be used as a general light source.

The development and application of fluorescent powder, high brightness LED various colors of the breakthrough, the luminous efficiency is increased by about 1000 times, color has achieved all colors of the visible light band, one of the most important is the emergence of super high brightness white LED, LED applications across the high efficiency lighting market as possible. It has been pointed out that the high brightness LED will be one of the greatest inventions of mankind after Edison invented incandescent bulbs. In recent years, with the research on semiconductor luminescent material continuously thorough, continuous progress and new material manufacturing process (LED nitride crystal and fluorescent powder) in the development and application of ultra high brightness LED color has made a breakthrough, the luminous efficiency is increased by about 1000 times, color has been achieved all the colors of the visible light band, one of the most important is the emergence of super high brightness white LED, make LED applications across the high efficiency lighting market as possible. It has been pointed out that the high brightness LED will be one of the greatest inventions of mankind after Edison invented incandescent bulbs.

(two) LED luminescence principle

The light-emitting diode is mainly composed of PN junction chip, electrode and optical system. The luminous body - the area of the chip is 10.12mil (1mil=0.0254 mm2), there is a large chip LED, chip area of 40mil.

The greater the energy (band gap) between the electron and the hole, the higher the photon energy. The photon energy in turn corresponds to the color of the light spectrum in the range of visible light, blue light, purple light energy carried up, orange light, red light energy to carry at least. Because different materials have different band gaps, which can emit different colors of light. The luminescence process consists of three parts: carrier injection, composite radiation and optical energy transmission under forward bias. A small semiconductor chip is encapsulated in epoxy resin cleaning, when the electron through the wafer, negatively charged electrons move into the cavitation zone positively charged and composite, and the electrons and holes produce photon disappear. The greater the energy (band gap) between the electron and the hole, the higher the photon energy. The photon energy in turn corresponds to the color of the light spectrum in the range of visible light, blue light, purple light energy carried up, orange light, red light energy to carry at least. Because different materials have different band gaps, which can emit different colors of light.

LED lighting source will be the mainstream of high brightness white LED. At present, the commercialization of white LED is more than two wavelengths, that is, a blue chip with YAG yellow phosphor mixed to produce white light. The future is promising is the three wavelength white light LED, which is using inorganic UV chip plus a mixture of red, blue and green three color phosphor white light is generated, it will replace the fluorescent lamp, compact fluorescent lamp and LED backlight market.

(three) the basic characteristics of LED light source

1, high luminous efficiency LED after decades of technological improvements, the luminous efficiency has been greatly improved. Incandescent lamp, halogen light effect of 12-24 lumens / watt, fluorescent lamp 50 ~ 70 lumens / watt, sodium lamp 90 ~ 140 lumens / watt, most of the power consumption into heat loss. LED light effect will be improved by up to 50 ~ 200 lumens / watt, and its good monochromatic light, narrow spectrum, without filtering can be issued directly colored visible light. At present, all the countries in the world are stepping up efforts to improve the research of LED light efficiency, and its luminous efficiency will be improved in the near future.

2, less power consumption LED single tube power of 0.03 ~ 0.06 watts, using DC drive, single tube drive voltage of 1.5 to 3.5 volts, current of 15 to 18 Ma, fast response, can operate at high frequency. The same lighting effect, power consumption is 1/8 of incandescent bulbs, fluorescent tubes, 1/2 Japanese estimates, such as the use of incandescent lamp and fluorescent lamp fluorescent lamp with high light efficiency more than two times the LED replace half of japan. Annual savings equivalent to 6 billion liters of crude oil. Bridge guardrail lamp, a fluorescent lamp of the same effect more than 40 watts, and the use of LED power each only 8 watts, and color change.

3, the use of long life, the use of electronic light field radiation, filament light burning, thermal deposition, light attenuation and other shortcomings. The LED lamp is small in size and light in weight, and it can withstand high strength mechanical shock and vibration. Average life of 100 thousand hours. LED lamp life of up to 5 ~ 10 years, can greatly reduce the maintenance costs of lamps and lanterns, to avoid the frequent change of light.

4, high safety and reliability low heat, no radiation, cold light source, can be safely arrived at touch: can accurately control the light type and angle, soft light, no glare; no mercury, sodium may be a health hazard. The built-in micro processing system can control the luminous intensity and adjust the lighting mode to realize the combination of light and art.

5, is conducive to environmental protection LED light for all solid body, shock resistance, impact resistance is not easy broken, waste Recyclable, no pollution. The light source is small in size and can be assembled at will, which is easy to be developed into a light, thin, short and small lighting product. Of course, such is the main reason we consider using LED light source, LED light source may be expensive than the traditional light source, but with such a year to recover the source of investment, resulting in 4 ~ 9 years every year several times such period of net income.

Two, LED lighting source technology application prospects and trends

For a long time, due to the low light efficiency of LED, its application is mainly concentrated in a variety of display areas. With the appearance of ultra high brightness LED (especially white LED), it is possible to apply in the field of illumination. According to international authorities predict that in twenty-first Century will enter the LED as the representative of the new era of lighting source, known as the fourth generation of new light source.

(a) the prospect and development trend of the entire lighting consumption accounts for about 20% of the electricity consumption, reduce lighting electricity is an important way to save energy, to achieve the goal of the industry has developed many kinds of energy-saving lighting appliances, and achieved some success. However, the distance from the "green lighting" is not enough, the development and application of more efficient, reliable, safe and durable new light source is imperative. LED is attracting the world's attention because of its inherent superiority. The United States, Japan and other countries and Taiwan area to predict the LED lighting efficiency, fluorescent lamp and incandescent lamp 55% us 55% replaced by LED, annual electricity savings of 35 billion U. s.dollars, an annual reduction of 7.55 tons of carbon dioxide emissions. Japan's 100% incandescent lamp for LED, can reduce the amount of energy from 1 to 2 nuclear power plants, annual savings of more than 1 billion liters of crude oil consumption. Taiwan area 25% incandescent light bulbs and fluorescent lamps are replaced by white LED, an annual savings of 11 billion kwh of electricity. Japan as early as 1998 on the preparation of the "twenty-first Century plan" for the new century lighting with LED light source for practical research. In recent years, Japan's Nichia chemical synthesis, SONY, TOYOTA, LED etc. have Jiayou electrical lighting products come out. The world famous lighting companies such as PHILPS, OSRAM, GE and so on also invest a lot of manpower and material resources to carry out research and development and production of LED lighting products. The United States GE company and EMCORE company to set up a new company, specializing in the development of white LED, to replace the incandescent lamp, compact fluorescent lamp, halogen tungsten lamp and car lights. OSRAM and SIEMENS co develop LED lighting system. Taiwan's current LED output after Japan in the United States before, from 1998 began to invest 600 million yuan to carry out related work. LED has been developing for decades, but it is still a new technology in the field of lighting. With the rapid development of LED technology, its light-emitting efficiency gradually improve, LED application market will become even more widely, particularly in the global energy shortage fears rise again in the background, LED lighting market prospects in the global attention, the industry was that in the next 10 years to become the most promising market and largest market is the largest commercial potential to replace incandescent lamps, incandescent light and fluorescent lamp.

(two) the main technical problems in lighting application in recent years, the luminous efficiency of LED is gradually improving, the commercialization of the device has reached the level of incandescent lamp, landscape lamp with white LED luminous efficiency close to the fluorescent lamp, and steadily growing. However, there are still some technical problems in the popularization and application of lighting: first, the luminous flux needs to be further improved. Using LED as a lighting source, it must be able to emit more light and must have higher energy efficiency. Two is the light emitted by LED and natural light is still a certain gap. Incandescent lamp has a very strong yellow light component, gives a warm feeling. The white LED light emitting white light with the composition of the blue light in this light, people's vision is not very natural. Three is the higher price. This is the main reason for the popularity of LED lighting. However, for the improvement of chip technology in recent years, the manufacturing cost is decreased sharply over the past three years, LED prices fell by nearly 50%, which is moving to the direction of high efficiency and low cost, which provides favorable conditions for the application of LED in the field of lighting. In addition, a better price can also make up for the lack of cost price.

Three, LED lighting technology in the lighting environment

Because of the high luminous efficiency of LED light source