1.Introduction  

 

The structure of modern automobile lamps is becoming more and more complicated, at the same time the function is being improved gradually. The development of automobile lamps has experienced four stages. The first generation of automotive light source is fuels (candles, coal oil or acetylene). These fuels burn to emit lights. Fuels can only satisfy the requirement of early stage automobile lamps due to its low luminous efficiency, weak light intensity, unstable performance, complex operation and etc. shortcomings.

Common infrared LED that emits infrared rays has the same appearance with visible light LED. Its appropriate operating voltage is around 1.4v and the current is generally smaller than 20mA. Current limiting resistances are usually connected in series in the infrared LED circuits to adjust the voltages, helping the LEDs to be adapted to different operating voltages.

LED fluorescent lamp is the newest product line in the fluorescent family and is considered to be the final replacement for traditional fluorescent lamp. It is made up of white LED chip modules. Provided with the advantages of long life-span, radiation-free, energy saving, environmental friendly and stroboflash-free, LED fluorescent lamp is superior to other kinds of lamps.

LED lumen attenuation is the weakening of the light signal during transmission. LED products made by global leading manufacturers at the present stage have lumen attenuation in different grades after used for a period of time and this phenomenon also exists in high power LEDs. Then, what causes LED attenuation? Lumen attenuation is directly related to the temperature, and is mainly determined by the chip, phosphor used and the packaging technology. At present, lumen attenuation has become the chief problem for white LED to march into civil lighting field.

LED luminous letter (or caption machine) adopts light emitting diode as lighting source. It is usually installed on the top of buildings or on wall surface in the shape of given letters or signs. LED luminous letter chooses high brightness LED chips and uses specific system to take control of the dynamic video of the letters or signs. The unique designed LED luminous letter surpasses the traditional outdoor advertisement in function. Its abundance colors make it much superior than traditional neon light and make break through in application variety.

LED which is becoming widespread owns various kinds of product. LED products can be classified into different types according to light emitting colors, outer surface trait and structure of the diodes, luminous intensity, operating current, chip material, function and etc. This passage is going to introduce four types of LED products classification. 1. According to light emitting colors of the diode: LEDs are available in red, orange, green (subdivide into yellow-green, standard green and pure green) and blue and so on.

LED brightness can be improved through the following two methods: 1. To increase the light output of the chip itself: light output can be increased through improving the luminescence efficiency of the chip’s active layer or improving the external light extraction efficiency by optimizing chips’ shape or making larger scale chips that run high density current.

LED is the acronym of Light Emitting Diode. It is a kind of semiconductor device that is commonly used in indicator light and display board. LED is capable of transforming electric energy into light energy directly in high efficiency and its life-span can reach as long as tens of thousands hours to one hundred thousand hours. Compared to traditional bulbs, LED also bears the advantages of non-friable and power-saving and so on.

Alone with the extensive application of LED in every trade, high power LED is widely adopted as light sources in traffic, railway and electronic equipment signal lamps. As defined by its name, high power LED is provided with higher power and heat, with larger lumen than ordinary LED, thus enable it to shine brighter. Strict requirements are posed on the selection of high power LEDs used in signal lamps. Ordinary LED can not be used as signal lamps at random for the following reasons:

Nowadays, LED products are being used in numeric displays and indicator lights to a range of new and potential new applications, including exit signs, accent lights, task lights, traffic lights, signage, cove lighting, wall sconces, outdoor lighting and downlighting.The following is the list of LED applications:•    Streetlights•    Large scale video displays•    Architectural lighting•    Status indicators on all sorts of equipment

At present, three kinds of reading lamps are commonly seen in market: the traditional incandescent reading lamp, the halogen reading lamp and fluorescent reading lamp.The incandescent reading lamp and the halogen reading lamp are cheap and emit the light with good continuity, yet they consume much energy and produce heat. If the power is high, they shine too much to make people dazzle; if the power is too low, the intensity of illumination is lower than requested.

LED stands for "light-emitting diode," a relatively new source of light. According to Wikipedia, the principle of generating light with a solid-state device was discovered early in the 20th Century, but it wasn't until the 1960s that useful LEDs became commercially available. Only recently have LEDs developed in brightness and color technology to be considered as sources of area illumination.

A diode is the simplest sort of semiconductor device. Broadly speaking, a semiconductor is a material with a varying ability to conduct electrical current. Most semiconductors are made of a poor conductor that has had impurities (atoms of another material) added to it. The process of adding impurities is cal doping.

1. Characterizing a Light Source

A new screen technology promising sharper and more vivid images, longer battery life and slimmer designs promises to become the standard display for laptops, pumping fresh life into the PC industry.A crop of sleek, design-led laptops, featuring light emitting diode (LED)-backlit displays was on show at the Computex trade fair in Taiwan this week, using technology once the preserve of smaller gadgets such as toys, music players and mobile phones.

Conserving energy is now a mandate, not a choice, and part of that mandate is the need to go Green. When it comes to lighting, we can easily imagine the impact of globally improving the efficiency of lighting sources by 10 percent. But what if it could be improved by 1,000 percent?

A. LED displays can be classified into two types according to locations applied: indoor LED display and outdoor LED display1. Indoor LED display

Advanced Analogic Technologies has introduced a 2-MHz boost-converter IC that uses a supercapacitor to provide a large peak current to an LED-flash system. The 2A AAT1282 flash driver incorporates I2C control and accepts input voltages of 2.7 to 5.5V. Designers can use the device's two 1A current sinks to drive two LEDs and can parallel these outputs to drive one 2A LED. The IC allows designers to set 16 levels for movie, or "torch," mode and has a true-load-disconnection feature that guarantees a shutdown current of less than 1 μA.

OSRAM, together with its partners in the LED-Light-for-you (LLFY) network, is promoting LED technology for general lighting applications. The offered range of products, innovative technologies and services is showing the industry the way forward. The network is therefore ideally equipped to meet the demands of this fast-growing market segment.

InN material is a kind of excellent semiconductor materials and plays an important role in photoelectron field. Due to the huge application potential and the secrets of the characters having been revealed, the InN material has already been one of the most attractive materials in recent two years. InN film was synthesized by ammoniating indium film on Si (111) substrates, and there are two major problems in producing InN film currently.

Modern designers are just as innovative in their use of high-tech artificial light. All in all, it's a bright idea, as Martha Teichner now shows us: Revolutionary is the operative word, even if exuberant, dazzling, nifty, cool also come to mind.. Imagine light in 16 million colors … fabric that can soak up the sun during the day and illuminate the third world at night. No plugs, no lightbulbs.

LED (Light Emitting Diode) lights attract a great deal of attention as “a light for the 21st century”. This is the field where the market is fast growing as the LED light can be an alternative light source to a conventional incandescent bulb and fluorescent bulb. Compared to an incandescent lamp (bulb type), LEDs have lower power consumption and a longer lifetime. There are a number of advantages including being environment-friendly and having an excellent response speed.

Designed to be used on thin paper, Toyo Ink's "FD LED Series" of LED-UV curable offset inks consists of a range of offset inks hard dried using ultraviolet rays produced by dedicated light emitting diodes (LEDs). Although the "FD LED Series" achieves the same level of ink performance as UV curable inks dried using conventional UV lamps, it is lined up as a next-generation technology due to the fact that it reduces environmental impact by conserving energy. It is aimed squarely at users focused on printing innovation.

Light-emitting diodes save energy. In terms of their light output, however, they have so far been unable to compete with light bulbs. A new, low-priced optical component is set to change that situation: It concentrates the light and directs it precisely to where it is needed.

Scientists have found a way to increase the light-output efficiency of LEDs through pioneering nanoelectronics. Dr Faiz Rahman is putting millions of holes into light emitting diodes to make them brighter. He's not, as you might imagine, trying to increase their surface area. Instead, he's overcoming the physical properties that keep most light trapped inside. And when he's managed to scale up his hole-making process, it'll mean bright low-energy LED light bulbs for the home.

As we all know, single electrode chip package has quite high requirement of die attach, thus the silver adhesive is required to be handled strictly. Maybe the problems won’t show in the process of production, but the abnormal situations such as the power-off may be encountered when the customer uses it.Because there hasn't a copy of notices proclaimed in writing concerning the usage of LED die attach silver adhesive, the following items are concluded according to industrial experiences for readers’ reference.

 The U.S. based "Lighting Science Group (LSG)" has announced the launch of its new line of LED light bulbs. The new product series, which include the industry's widest line of LED lamps, were specially designed for both commercial and residential lighting applications.

The same innovation that makes laptop screens thinner turns out to be one of the best energy-saving technologies on Earth - and it's all thanks to new tricks that make it possible to create more illumination using the most humble member of the semiconductor family, the light-emitting diode, or LED.