LED Lighting that is LED Lighting, full name is the Lighting Emitting Diode, is a semiconductor solid glowing device. It is using solid semiconductor chips as luminescence materials, in a semiconductor through the charge carriers happen out the excess energy compound and cause photon emission, an immediate red, yellow, blue, green, green, orange, purple, white light. LED lighting products is to use as the light source made LED lighting apparatus.
LED lighting principle:
LED by III-IV is the compounds, such as GaAs (gallium arsenide), GaP (phosphating gallium), GaAsP (p gallium arsenide) made of semiconductor, its core is the PN junction. So it is generally P-N -N characteristics, that is, is the guide, reverse globe, breakdown characteristic. In addition, with a certain conditions, it also has the luminescence properties. The positive voltage and electronically by N area into the P area, cavitation by P area into N area. Into each other area of minority carriers (ShaoZi) with majority carrier (many children) composite and shine.
Light is that in P happened in the area, so the injection of electronic and valence band hole direct compound and shine, or to capture light center, then and hole composite luminescence. In addition to this kind of glowing compound outside, still some electrons are the luminous center (the center between the conduction band, interface among with nearby) capture and then and hole compound, every time release energy is not big, cannot form visible light. The shine of compound in the relative amount of light the proportion of composite, the greater the light quantum efficiency is higher. Because in the ShaoZi composite is the spread of light, so light only in the near PN junction plane μ m produced several within.
Type in the unit for Eg electron volts (eV). If can produce visible (in 380 nm wavelength) to 780 nm red light), semiconductor materials should be in Eg 3.26 ~ 1.63 eV between. More than red light wavelength long light for infrared radiation. Now had the infrared, red, yellow, green and blue leds, but the blue light-emitting diode (led) cost, the price is very high, use not common.
LED lighting characteristics:
1. The meaning of the limit parameter
(1) allow power consumption Pm: Allow and in positive dc voltage and LED at both ends of the products of the current flows through it the maximum. More than this value, the LED fever, damage.
(2) the biggest positive dc current IFm: Allow the biggest positive with dc current. More than this value can damage the diodes.
(3) the biggest reverse voltage VRm: Allows the biggest and reverse voltage. More than this value, light emitting diode can be broken down.
(4) the work environment topm: Leds can effectively work environment temperature range. Below or above this temperature range, leds will can not work normally, the efficiency is greatly reduced.
Development present situation:
The current global energy shortage concerns rise again in the background of energy saving is facing in the future we important questions, in lighting field, LED product applications is attracting the worlds attention, LED as a new type of green light source products, inevitable is the trend of the development of the future, the 21 st century will enter the LED lighting source as a representative of the new era.
China LED industry started in the 1970 s. After 30 DuoNian development, China LED industry has been developed including LED the production of extension, LED chips preparation, LED chips encapsulation and LED product application, a complete industry chain. In the national semiconductor lighting project the promotion, formed the Shanghai, dalian, nanchang, xiamen, shenzhen, yangzhou and shijiazhuang seven countries semiconductor lighting project industrialization base. Long Yangtze river and pearl river delta, fujian triangle in the northern region of China and has become the LED industry development of the colony.
At present, China semiconductor lighting industry development reform, the development of enterprises especially extension chip quickly, packaging enterprise scale kept fast growth, lighting applications have made great progress. In 2007 China LED application products output value has more than 30 billion yuan, has become a full color LED display screen, solar LED lighting products, landscape application, the worlds largest in the production and export of semiconductor lighting industry is emerging form. Domestic lighting area has been formed in certain features, including outdoor lighting the fastest growing, there have been hundreds of LED street lamp enterprise and the construction of dozens of demonstration road, but domestic at large size LCD backlighting and automobile lamps still show lag behind.
The 2008 Olympic Games in Beijing to showcase the LED lighting to let people LED a new understanding, has promoted the development led lighting of China semiconductor lighting industry. Chis current semiconductor industry industry big but not strong, still to be core competitiveness in future ascension. To domestic companies, expand scale, improve product quality and technology level is the primary task, improve the future has a patent license for giant when ability, or gradually through the research breakthrough core patent.
Development trend:
Called the fourth generation LED lighting source or green light source, energy saving, environmental protection, long life, small volume and other characteristics, can be widely used in various instructions, display, adornment, back light, general lighting and city at night, etc. In recent years, some of the world economy around the development of the developed countries LED launched fierce competition of the technology. The United States since 2000 investment of 500 million us dollars to implement the national semiconductor lighting plan, the eu is also announced in July 2000 start similar rainbow plan. The ministry of science and technology in the 863'' program, under the support of June 2003 was the first to propose development semiconductor lighting plan.
Advantages:
High energy saving, energy saving energy that is free from pollution for environmental protection. Dc drive, low power consumption (single pipe 0.03-0.06 watts) lightning power conversion close to 100%, the same lighting effect than traditional light energy saving 80% above.
Long life: Some called it LED light source for longevity lamp, meaning never put out the lamp. Solid cold light source, the epoxy resin packaging, light body and no loose parts, there is no filament burn, thermal deposits to shine, light failure shortcomings, service life can reach 60000 to 100000 hours, than traditional light source long life to 10 times.
Many changes: LED light source available red, green, basket three colors principle, in computer technology control make three color with a level 256 gray and arbitrary mixed, can produce 256 x 256 x 256 = 16777216 kinds of color, light color combination form different changes frequently, and realize the dynamic changes of rich and colorful effect and various kinds of images.
The environmental protection: Environmental protection is more effective, ultraviolet and infrared spectrum no, no heat, no radiation, glare small, and waste recycling, no pollution contains no mercury elements, and cold light source, safe to touch, belongs to the typical green lighting source.
High point: And the traditional light source drab glow effect compared, LED light source is low voltage microelectronics products, successful blend computer technology, network communication technology, image processing technology, embedded control technology, so also is the digital information product, is the semiconductor photoelectric device high point technology, with online programming, infinite upgrade, flexible characteristics.
Terms:
Wavelength: The colour of light intensity change, can be through the data to describe, the data that wavelength. We can see the wavelength of the light, range in the 380 to 780 nm between. Units: Nano (nm)
Brightness: Brightness is refers to the degree of light and shade objects, unit area is defined the luminous intensity. Units: Nita (nit)
Light intensity: Refers to the degree of bright light source. That said in a certain direction and scope of light inside an visible spectrum of the strength of the physical quantities.
Units: Candle (CD)
Flux: The light source from every second of quantity of visible light combined. Units: Lumen (Lm)
Efficacy: Light source of the flux of the light source, divided by a power. It is an important index of the energy conservation measure light source. Units: Each tile lumen (Lm/w).
Show color sex: Light source of object of the present level, that is the color of verisimilitude. Often called the colour developing index unit: Ra.
Color temperature: Light source the light color and launch bold in a temperature radiation light hue and at the same time, the temperature of the bold colour temperature is called the light source.
Units: Kelvin (k).
Glare: There were extremely tall brightness view objects or the brightness of the strong contrast, caused by visual not comfortable called glare, influence the quality of the light is lighting glare important factors.
Synchronicity: Two or more than two LED lamp in time according to provisions can normal program running way, generally refers to the way of internal control LED lamp, synchronicity is LED lamp accomplish coordinated change basic requirements.
Protection level: IP protection grade will be in accordance with its lamps and lanterns is dustproof, and the characteristics of moisture to grade, composed by two Numbers, the first number represents lamps and lanterns dustproof, prevent external things of committed level (points 0-level 6), the second number represents the lamps and lanterns of moisture, waterproof committed sealing (points 0-eight level), the greater the number said its protection grade is higher.
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