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Dec 19 2017

Contemporary LED Lighting Technology and Application in Our Daily Life

Warm hints: The word in this article is about 3200 and  reading time is about 20 minutes.

Ⅰ Introduction

Recent years, with the rapid development of industrialization and urbanization, the supply and demand of energy and resources is becoming increasingly tense, which has had a certain negative impact on the power supply. LED lighting application, because of its energy-saving, long lifespan, eco-friendly, small size, fast response, high reliability, easy control and many other advantages, is getting more and more widely used as a new type of lighting. This article will focus on the specific discussion of the new energy-saving light source LED development prospects and its market demand from the principle of LED lighting technology and application.

Light-emitting Diode Characteristics, Working & Application

Catalog

Ⅰ Introduction

Ⅱ LED Terminology

2.1 LED Lighting Principle and Characteristics

2.2 LED Technology Development

2.3 LED Lighting Principle

2.4 LED Lighting Characteristics

Ⅲ LED Lighting Applications

3.1  Application of LED Street Light

3.2  Application of Urban Landscape LED Lighting

3.3 Applications of Advertising lighting

IV Conclusion


Ⅱ LED Terminology

LED ( Lighting Emitting Diode), is a semiconductor solid - emitting device. It is used as luminescent materials using solid semiconductor chips in the semiconductor carrier occurs through release of excess energy complex caused by photon emission, directly emit red, yellow and blue and green light, on this basis, using the principle of three primary colors, adding fluorescent powder, can send out any color of light. The illuminator made by using LED as the light source is the LED lamp. LED lighting, reflective use of LED lighting can be fully qualified for any occasion, large area of indoor lighting is not mature.

2.1 LED Lighting Principle and Characteristics

2.1.1 An Overview of Light-emitting diode(LED)

Light-emitting diodes(LED) is a diode made of a compound of gallium (Ga),arsenic (As), phosphorus (P), nitrogen (N) and indium (In). When electrons recombine with electron holes within the device, they will emit visible light; thus they can be made into light emitting diodes and applied as indicator lights in the circuit and equipment. Gallium arsenide phosphorus diodes produce red light, gallium phosphide diodes produce green, silicon carbide diodes produce yellow, and indium gallium nitride diodes produce blue.

It is a kind of semiconductor diode that converts electrical energy into light. Light-emitting diodes and those ordinary diodes are both composed of a PN junction, and also have unilateral conductivity. In different semiconductor materials, electrons and holes are in different states of energy. So when electrons and holes are recombined, the released energy is somewhat different. The more energy is released, the shorter the wavelength of light is emitted. Nowadays the commonly used diodes are red, green or yellow light.

LED structureRGB

2.2 LED Technology Development

With the global consensus on the development of low-carbon economy, LED lighting industry is ushering in valuable opportunities for rapid development with its performance advantages in the field of energy saving. In the current low-carbon economy, LED lighting industry is heating up and the competition is getting fiercer. LED, known as the fourth generation of light source or green light source and with characteristicss of energy-saving, long lifespan, eco-friendly, small size etc., can be widely used in various fields like indications, display, decoration, backlight, general lighting and urban landscape lighting... Some developed countries in the world have launched a fierce technical competition focusing on the development of LED. The United States has invested 500 million U.S. dollars in implementing the "National Research Program on Semiconductor Lighting" since 2000, and the EU announced the launch of a similar "Rainbow Project" in July 2000. China's Ministry of Science and Technology proposed the development of semiconductor lighting program with the support of the "863" program in June 2003.

Over the years, LED lighting has won great attention from many countries and governments with its energy-saving and environmental advantages. Most countries have introduced relevant policies and initiatives to speed up the development of LED lightin. At the same time, mass consumers are also desiring long for this new environmentally friendly lighting products.

 

2.3 LED Lighting Principle

The LED light source LED is made of III-IV compounds, such as GaAs (gallium arsenide), GaP (gallium phosphide), GaAsP (gallium arsenide phosphide) and other semiconductors, the core of which is the PN junction. Under certain conditions, it also has the luminous characteristics. In the forward voltage, electrons are injected into the P region from the N region, and holes are injected into the N region from the P region. Part of the minority carrier (minority carrier) entering the other area and the majority carrier (multiple carrier) recombine to emit light. Assuming that luminescence is occurring in the P region, then the injected electrons will directly recombine with the valence band holes to emit light. Or they will be first captured by the luminescent center and then recombined with the holes to emit light. Apart from this luminescent composite, some electrons will be captured by the non-luminescent center (the center is near the middle of the conduction band and the conduction band) and then recombine with the holes. Each time the released energy is not large enough to form visible light. The greater the ratio of luminescence complex amount to the non luminescent complex, the higher the quantum efficiency will be. Since recombination emits light in the minority-diffusion region, light is generated only within a few μm near the PN junction.

LED Lighting Principle

 

The theory and the practice show that the peak wavelength  of light λ is related to the bandgap Eg of the semiconductor material in the light-emitting region, that is, Eg in λ≈1240 / Eg (mm) is in units of electron volts (eV). If you can produce visible light (wavelength 380nm violet ~ 780nm red), Eg of the semiconductor material should be between 3.26 ~ 1.63eV. The light of longer wavelength than the red light is infrared light. Now there are infrared, red, yellow, green and blue light-emitting diodes, but the cost of blue-diode is high, so it is not widespread.

  • Figures: Colors and Materials

Color

Wavelength[nm]

Voltage drop [ΔV]

Semiconductor material

Infrared

λ > 760

ΔV < 1.63

Gallium arsenide (GaAs)

Aluminium gallium arsenide (AlGaAs)

Red

610 < λ < 760

1.63 < ΔV< 2.03

Gallium arsenide phosphide (GaAsP)

Orange

590 < λ < 610

2.03 < ΔV< 2.10

Aluminium gallium indium phosphide (AlGaInP)

Yellow

570 < λ < 590

2.10 < ΔV< 2.18

Aluminium gallium indium phosphide (AlGaInP)

Green

500 < λ < 570

1.9< ΔV < 4.0

Aluminium gallium indium phosphide (AlGaInP)

Blue

450 < λ < 500

2.48 < ΔV< 3.7

Indium gallium nitride (InGaN)

Violet

400 < λ < 450

2.76 < ΔV < 4.0

Indium gallium nitride (InGaN)

Purple

Multiple types

2.48 < ΔV< 3.7

Dual blue/red LEDs,

blue with red phosphor,

or white with purple plastic

 

2.4 LED Lighting Characteristics

  • Energy-saving

Research data show that, as LED is a cold light source, the semiconductor lighting itself has no pollution to the environment.Compared with incandescent and fluorescent lamps, its energy-saving efficiency can reach over 90%. At the same brightness, the power consumption is only 1/10 of ordinary incandescent and 1/2 of fluorescent tube. If we replace 50% of our traditional lighting with LEDs, the annual electricity saved in our country is equivalent to the sum of the electricity generated by the Three Gorges Power Station and its energy-saving benefits are substantial.

  • Healthy

LED is a green light source. LED lights are DC drived with no stroboflash, no infrared and ultraviolet components, radiation pollution while with high color rendering and strong light direction. What’s more, due to its good dimming performance, it will not produce visual error when the color temperature changes. As the cold light source produce low heat, you can touch the LED safely.All these are advantages that incandescent and fluorescent can not reach. LED can not only provide a comfortable light space, but also meet people's physical health needs.

  • Artistic

LED lighting has shows its unparalleled advantages in the art of light color display. Color LED products have covered the entire visible spectrum.They are good monochromatic with high color purity.The combination of red, green, yellow LED provides a greater flexibility of choice. We can utilize the combination of bright and dark optics in optical technology , the combination of light and color more flexibly. And enhance the freedom of design to weaken the lighting function of the lamp so as to make the lamp a visual art and create a comfortable and beautiful light art effect. 

 

Ⅲ LED Lighting Applications

3.1  Application of LED Street Light

Road lighting is closely related to people's life. With the acceleration of urbanization in our country, LED street lights have stepped into mass vision due to its advantages of directional lighting, low power consumption, good driving characteristics, fast response, high seismic capacity, long service life and environmental protection and become the world's most energy-efficient alternative of a new generation of light sources; therefore,LED lights will be the best choice for energy-saving road lighting.

The United States plans to set 140,000 LED street lights within five years and Utah has started the bidding for LED street lights. It has announced the replacement of 1.28 million LED street lights within three years.

street light

3.2  Application of Urban Landscape LED Lighting

  • LED Lighting Era

1) Full access to LED lighting era

LED lighting products have been widely used in landscape lighting market, quickly led to the rapid growth of the lighting market , and helped landscape lighting to occupy the largest market share of LED lighting applications branch with its excellent color performance, light color change extremely strong control, small size and energy saving, stability and other characteristics. 

Urban Landscape LED Lighting

2) Decorating the City Landscape

CUSTOMIZED, literally, can be understood as tailor-made products or services tailored to the needs of the customer. "Customized" has been frequently used in clothing, shoes and hats, jewelry and other fields. With the development of the times, the meaning of customize has gradually been enriched. Custom landscape lighting products can maximize the designer's creativity and imagination, landscape lighting designer's special brush. Architects and designers will no only select suitable light sources, but also consider from the light effects and environmental effects as well as materials, texture and reliability considerations, focusing on the unity of the natural environment and lighting.Customized lamps is out of the traditional concept of homogeneous design. As designers love, they have been more and more used in landscape lighting projects.

3) Intelligent Control Leads the Technical Lighting

LED lighting products are widely used in major domestic events and venues, parks. One of the reasons is that its intelligent control system is superior than the traditional lighting products. The integration of management and control makes it easy to control the real-time status of lighting projects. The integration of management is a key technology for lighting energy saving with proper control strategy. LED is programmed and controlled according to the overall requirements of the environment. Through the coordination of LED light colors, the overall artistic landscape effect can be produced.

 

  • Lighting Lamp Project

Good quality lamps and lanterns lighting project is the basis of quality assurance. LED light source has different principles of traditional light, so its lighting design from the internal structure to the external shape and also need to comply with the LED device itself from the perspective of special design and manufacture.

1) Decorative lawn lamp, landscape lamp, bulb

In urban streets or green spaces, the glowing parts are designed in various forms, such as rings and ribbons, to locally illuminate the lawn; at the same time, they become decorative elements in the daytime environment. Common products are rated voltage AC220V, control methods are mostly internal control (in the need to synchronize changes in the place can be used to achieve synchronization forced synchronization). The actual project is often used together with the gas discharge lamp as a decorative lighting. The use of lawn lamp, landscape lamp, bulb and other different shapes, different functions of the LED light source can be combined into a colorful light illusion. This "multi-color, bright spots, multi-pattern" changes reflects the characteristics of LED light source.

lawn lamp

2) Underwater lights

Underwater LED lights is used as lighting of the water body under the water,whose protection level should reach IP68. The rated working voltage is DC12V. Low-voltage LED operating characteristics make it safer than any previous lamp.Its long lifespan advantages also make it easier to maintain, which resulting in more profound lighting effects than the usual PAR lamp, gas discharge lamp.

underwater lightunderwater landscape

3) Ground lamps: buried lights, luminous tiles, stone lights

Ground lamps using LED light source can be miniaturized. On the one hand it can be used as ambient lighting, on the other hand it can be used as decorative lighting or guiding function lighting. Depending on the concrete structure of the surface of the light distribution area, the pavement can be enlarged or downsized. Embedded stone lamp, brick light trimming processing methods and paved stone are made consistent to achieve harmony between the environment and light effects.

buried light

3.3 Applications of Advertising lighting

  • Water Advertising Lights

As an element of modern decoration, water advertising lights are applied to many places such as many entertainment places, barbershop, hotels, restaurants, companies outside the door. We can see a wide range of advertising lights. The so-called advertising water lights, is a series of advertising lights in series together, and then make these lights by a certain order one by one or several turn on or off. As advertising lights lit effect is like running water, so they are called water advertising lights.

advertising lighting

  • LED Light Box

LED advertising light box constantly flash with stay, effectively improving people's visual impact. Also it improves the advertising unit area utilization, and the advertising effect of transform light boxes and rolling light box is indescribable. LED advertising light box set all the advantages of neon lights into one. It can constantly flash day and night. The combination of static and dynamic has successfully drawn the attention of people. Those various texts, patterns are orderly jumping and alternately shining with a strong visual impact. Thus it will satisfy the viewer's visual experience and then promote advertisers to maximize their economic efficiency. LED electronic flashing light box will be a shining pearl in the future advertising industry.

 

IV Conclusion

Over the past 10 years, LED have undergone great changes in the type of color, brightness and power. LED plays a traditional light source unparalleled role with its amazing and delightful application in the city indoor and outdoor lighting . The life of LED is up to 100,000 hours, which means that if it works for eight hours a day, you can have 35 years of maintenance-free theoretical protection. With low voltage operation, higher light output and low to zero output dimming, you can combine thousands of light colors, and the light-emitting area can be very small, even be made into 1 square millimeter. After two optical design, lighting can achieve the ideal light intensity distribution. The rapid development of LED technology will bring new possibilities for lighting design and application, which is many traditional light sources can not achieve. The development of white LED technology is promoting the progress of energy-saving lighting system.

For more details about LED Basics, you can watch this video:

A General Overview of LED Lighting Technology

 

Recommanded Reading

Light-emitting Diode Basics Tutorial

LED Lighting Circuit Protection

The Basic Introduction to Light-emitting Diode

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pinglun 4 comments

    • pingluntus
    • Www.Tcpwireless.Com on 2018/8/21 7:48:40

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    • pingluntus
    • cccam server on 2018/10/5 17:14:24

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    • pingluntus
    • Sonia on 2018/10/22 20:26:45

    I like the report

    • pingluntus
    • Musically Login on 2019/3/3 3:05:45

    Keep on writing, great job!

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