#lighting field

LED light source in the lighting field, the product of the semiconductor light-emitting materials, rapid technological development and the concept of "green light" gradually gained recognition. The "green light" to the field of foreign lighting in the 1980s proposed a new concept, the China Green Lighting Project "implementation began in 1996. An important step to achieve this plan is to develop and promote the efficient, energy-efficient lighting appliances, lighting to save electricity, reduce the environmental and light pollution, the establishment of a quality and efficient, economic and comfortable, safe, reliable, environmentally friendly lighting systems

First, the concept of LED high bay(LightEmittingDiode), also known as light-emitting diodes, solid semiconductor chip as a light-emitting materials, and ends with a positive voltage, the carrier in the semiconductor compound to release excess energy photon emission producing visible light.

(A) the history of LED development.

The application of semiconductor PN junction made of a light source principle LED come out in the early 1960s, the first red light-emitting diodes in 1964, followed by a yellow LED. Until 1994, blue, green LED developed. 1996 by Japan's Nichia Corporation (Nichia) successfully developed a white LED. LED with its inherent characteristics, such as energy-saving, long life, vibration resistance, fast response, cold light source, which is widely used in the field of light, lights, display, landscape lighting can be seen everywhere in our daily lives , household appliances, telephones, instrument panel lighting, car fog light, traffic lights and so on. However, due to its brightness is poor, expensive constraints can not be used as general-purpose light source application. In recent years, with the deepening of the semiconductor light-emitting materials research, development and application of the continuous advancement of the LED manufacturing process and new materials (nitride crystal and phosphor), a variety of colors, high brightness LED made a breakthrough , the luminous efficiency is improved nearly 1,000 times the chroma has achieved all the colors of the visible light, one of the most important thing is that the emergence of high brightness white LED, LED applications across highly efficient lighting market as possible. It has been pointed out, high brightness LED human Following Edison invented the incandescent light bulb, one of the greatest inventions.

(B) LED light-emitting principle of light-emitting diode chip from the PN junction, the electrode and optical systems.

Its luminous body - the chip area 10.12mil (1mil = 0.0254 square millimeter), international large-chip LED, chip area of 40mil. Its light-emitting process consists of three parts: the forward bias carrier injection, combined radiation and energy transfer. Tiny semiconductor chip is packaged in clean epoxy resin material, when the electronics after the chip, the negatively charged electrons move to the positively charged the hole region and with the compound, the electrons and holes disappear at the same time to generate photons. The greater the energy (band gap) between the electrons and holes, the higher the energy of the photon. Photon energy, in turn, corresponds with the color of light in a spectral range of visible light, blue light, purple light carries energy up, orange light, red light energy to carry at least. Since different materials have different band gap, which can emit different colors of light. The mainstream of LED lighting will be high-brightness white LED. At present, the commercial white LED is more than two wavelengths, blue chip with YAG yellow phosphor mixed to produce white light. The future is more optimistic about the three-wavelength white LED, white, plus red, blue, green color phosphor mixed inorganic UV chip will replace the fluorescent lamps, energy-saving compact fluorescent bulbs and LED backlight market.

(C) the basic characteristics of the LED light source

1, high luminous efficiency, LEDs after decades of technical improvements, the luminous efficiency has been greatly improved. Incandescent lamps, halogen light efficiency of 12-24 lumens / watt fluorescent lamps from 50 to 70 lumens / watt, sodium 90 to 140 lm / W, most of the power into heat loss. LED luminous efficiency will be improved to achieve up to 50 to 200 lm / W, and its light color, narrow spectrum, no filter can be sent directly to the colored visible light. Currently, countries in the world are stepping up to improve the efficiency LED light in the near future, the luminous efficiency will be greatly improved.

2, less power consumption LED single-tube power from 0.03 to 0.06 watts, DC drives, single-tube drive voltage of 1.5 to 3.5 volts, 15 to 18 mA current, fast response, can be operated at high frequency. Under the same lighting effects, the power consumption is one ten thousandth of incandescent bulbs, fluorescent tubes, half the Japanese estimates, such as the use of the LED luminous efficiency than fluorescent lamps but also twice as high as alternative to the Japanese half of the incandescent and fluorescent lamps. Annual savings equivalent to 6 billion liters of crude oil. On the bridge parapet lamp cases, the same effect of a fluorescent lamp more than 40 watts, while only 8 watts of power each LED can be colorful changes.

3, long life light-emitting electron beam radiation, filament light easy to burn, heat deposition, light attenuation and other shortcomings. The use of LED lights, small, light weight, epoxy package can withstand mechanical shock and vibration of high intensity, not broken. The average life expectancy of 100,000 hours. LED lamp life of up to 5 to 10 years, can significantly reduce lighting maintenance costs and to avoid the constantly changing light bitter.

4, security, reliability, low heat, radiant heat, cold light source can be safely arrived in touch: can precisely control the light pattern and light-emitting angle, soft light and color, no glare; no mercury, sodium and other potential health hazards substances. Built-in micro-processing system can control the luminous intensity, adjusting the light way to achieve light and art.

5, environmentally friendly LED light for all-solid-state, shock, impact resistance is not easily broken, recyclable waste, no pollution. Light, small size, can mix, easy to develop into a short small thin portable lighting products, but also easy to install and maintain. Of course, energy conservation is the most important reason we consider the use of LED light source, perhaps the LED light source expensive than traditional light sources, but recovered with a year of energy-saving light source investment to obtain the energy-saving net income of times each year in the 4-9 years .

Second, the LED lighting technology prospects and trends

A long time, the LED luminous efficiency reasons, its application is mainly in a variety of display areas. With the emergence of high brightness LEDs (white LED) may become in the lighting field. International authoritative institutions predict that the 21st century will be to enter a new era of lighting LED is known as the fourth generation light source.

(A) prospects and development trends

Currently, lighting consumes about 20% of the entire power consumption and greatly reduce electricity for lighting energy savings, to achieve this goal, the industry has research and development of many types of energy-efficient lighting apparatus, and achieved some success. From the "green light" is not enough, the development and application of more efficient, reliable, safe, durable, new light is imperative. LED with its inherent advantages are attracting the attention of the world. LED lighting efficiency, the United States, Japan and other countries and Taiwan were predicted, and 55% incandescent and 55% of the fluorescent LED to replace and save $ 35 billion per year of electricity, 755 million tons less carbon dioxide emissions each year. Japan 100% of the incandescent to LED, can be reduced to two nuclear power plant generating capacity, and annual savings of more than one billion liters of crude oil consumption. 25% of the Taiwan Area of the incandescent lamps and 100% of the fluorescent white LED, saving 11 billion kWh of electricity annually. Japan back in 1998 on the preparation of the "21st Century Plan to carry out practical research for the new century lighting with LED light source. In recent years, Nichia Chemical of Japan, Toyoda Gosei, SONY, the Jiayou electrician and so there are LED lighting products come out. World-renowned lighting companies such as Philips, Osram, GE has also invested substantial resources to research and development and production of LED lighting products. GE and EMCORE Corporation to set up a new company, specializing in the development of white LED to replace incandescent, compact fluorescent lamps, halogen lamps and car lights. Osram GmbH, Germany and Siemens to develop LED lighting systems. Taiwan's LED production is second only to Japan are listed in the U.S. before, from 1998 to invest NT $ 600 million related to development work. LED development history has been for decades, but the lighting in the area of new technologies. With the rapid development of LED technology, the luminous efficiency gradually increase the LED application market will be more extensive, especially in the context of the global energy shortage concerns rise again, the LED lighting market prospects for global attention, The industry believes that the most promising market as well as the largest market in the next 10 years, will also be the greatest potential to replace incandescent, tungsten and fluorescent goods.

(B) lighting applications the main technical problem

In recent years, LED luminous efficiency is gradually increase the commercialization of the device has reached the level of incandescent lamps, landscape lights white LED luminous efficiency close to the level of fluorescent lamps, and steady growth. Lighting wider application, however, there are still some technical problems: First, the luminous flux to be further improved. The LED as a light source must be able to issue more light, must have higher energy efficiency. LED light and natural light is still a gap. The incandescent lamp has a very strong yellow light components, gives a warm feeling. The composition of white light emitted by the white LED with a blue light under the illumination of this light, the people's vision is not very natural. Third, the higher prices. This is the main reason affect the popularity of LED lighting. However, in recent years for the improvement of chip technology, the manufacturing cost is a sharp decline, to the LED's price dropped by nearly 50 percent in the last three years, is moving in the high efficiency, low-cost direction for the application of LED lighting in the area provides favorable conditions. In addition, good value for money can make up for less than cost price.

Third, LED lighting technology in the lighting environment

LED light source with high luminous efficiency, less power consumption, long life, safety and reliability, there are environmentally friendly features, has been widely used in recent years in the environment of the city lights. Have been applied to the digital Symphony, fence lighting, plaza lighting, garden lighting, cast lighting, underwater lighting series. Many cities use the LED light source lighting technology used in the construction of urban lighting environment to produce good results, has accumulated a wealth of experience. Such as the Power Building in Guangzhou, Guangzhou Hedong Bridge, Guangzhou Industrial and Commercial Bank Building, Zhuhai welcome South lighting project, Dongguan central city lighting engineering, Zhengzhou, Henan Medical overpass, Shanghai Yan'an Road lighting project, Danyang flyover, Changde City, Hunan Nantong City communication tower lighting project.