The reality of climate change makes the use of energy on a global scale is under intense debate. Lighting is one of the most basic uses of energy in humanity. Today, the lighting means 19% of consumption of worldwide electricity. The low efficiency (about 5%) of old technologies and wasteful lighting highlight the need for improvements in this sector.
Solid State Lighting (SSL, for its acronym in English) has emerged as an alternative technology in lighting with a wide variety of applications. Light Emitting Diodes (LEDs, for its acronym in English) are SSL technology more available in the market, offers a variety of advantages over other lighting technologies, from the efficiency, robustness and longevity to the ability to generate directly a large number of colors. LEDs are currently available and rapidly replacing other light sources as well are now the preferred technology for decorative lighting and various applications. The power LEDs as a source of general illumination (white light), is currently one of their top prospects for the future. This paper presents the technology of LED lighting, focusing on their applications, life cycle and its ability to improve efficiency in lighting.
Why do we need alternatives?
different technologies are currently used in lighting. The oldest, incandescent lighting was originally invented in late 1800, and except for halogen lights, the lamp design has hardly changed since 1930. The most inefficient electric lighting, incandescent light, has a power conversion efficiency of light energy of only 5%. Despite this, they are the most widely used, mainly in the residential sector. Consume 30% of the electricity used for lighting while producing only 7% effective light. Now recognized the need to put an end to the use of incandescent lamps. The major lamp manufacturers reduced their production (BBC 2007) and the governments of different countries and presented initiatives to remove the lamps from the sale.
fluorescent lamps, the current strategy of interior lighting, 64% of electrically generated lighting accounts for 45% of electricity use for lighting. The efficiency of fluorescent lighting varies depending on the type of lamp, but usually is 5 to 8 times longer than incandescents. All fluorescent lamps contain mercury, although in dwindling numbers. Most fluorescent lamps emit ultraviolet light because of the way they work.
The other main group of lighting technologies, discharge lamps, are used in large spaces including outdoor, big halls and shopping malls. Discharge lamps provide 29% of light delivered, representing 25% of the electricity used in lighting.
Most of these types of lamps, produce only a limited variety of colors (eg sodium lamps produce the yellow color). This limits them to applications where color is not important. Some lamps are very efficient (much more than fluorescent lamps) and provide the amount of light needed for applications such as lighting. Still, you can still improve. The mercury vapor lamps, despite being an old inefficient technology that relies on a toxic metal, are used today. Discharge lamps produce light non-directional, making necessary the use of reflectors to ensure that light is directed to the desired direction. Due to poor design of outdoor lighting fixtures (including reflectors), lots of light is wasted resulting in a real reduction in efficiency, and light pollution.
is clear that, although there are a variety of lighting technologies in use today, none is perfect. Many options still have a low efficiency, mainly in residential lighting and specialty lighting. Many efficient products should resign other factors as the quality of color and toxicity. Clearly there is need for further responses to the increasing demand for artificial light, as is the case with LEDs.
Solid State Lighting (SSL, for its acronym in English) has emerged as an alternative technology in lighting with a wide variety of applications. Light Emitting Diodes (LEDs, for its acronym in English) are SSL technology more available in the market, offers a variety of advantages over other lighting technologies, from the efficiency, robustness and longevity to the ability to generate directly a large number of colors. LEDs are currently available and rapidly replacing other light sources as well are now the preferred technology for decorative lighting and various applications. The power LEDs as a source of general illumination (white light), is currently one of their top prospects for the future. This paper presents the technology of LED lighting, focusing on their applications, life cycle and its ability to improve efficiency in lighting.
Why do we need alternatives?
different technologies are currently used in lighting. The oldest, incandescent lighting was originally invented in late 1800, and except for halogen lights, the lamp design has hardly changed since 1930. The most inefficient electric lighting, incandescent light, has a power conversion efficiency of light energy of only 5%. Despite this, they are the most widely used, mainly in the residential sector. Consume 30% of the electricity used for lighting while producing only 7% effective light. Now recognized the need to put an end to the use of incandescent lamps. The major lamp manufacturers reduced their production (BBC 2007) and the governments of different countries and presented initiatives to remove the lamps from the sale.
fluorescent lamps, the current strategy of interior lighting, 64% of electrically generated lighting accounts for 45% of electricity use for lighting. The efficiency of fluorescent lighting varies depending on the type of lamp, but usually is 5 to 8 times longer than incandescents. All fluorescent lamps contain mercury, although in dwindling numbers. Most fluorescent lamps emit ultraviolet light because of the way they work.
The other main group of lighting technologies, discharge lamps, are used in large spaces including outdoor, big halls and shopping malls. Discharge lamps provide 29% of light delivered, representing 25% of the electricity used in lighting.
Most of these types of lamps, produce only a limited variety of colors (eg sodium lamps produce the yellow color). This limits them to applications where color is not important. Some lamps are very efficient (much more than fluorescent lamps) and provide the amount of light needed for applications such as lighting. Still, you can still improve. The mercury vapor lamps, despite being an old inefficient technology that relies on a toxic metal, are used today. Discharge lamps produce light non-directional, making necessary the use of reflectors to ensure that light is directed to the desired direction. Due to poor design of outdoor lighting fixtures (including reflectors), lots of light is wasted resulting in a real reduction in efficiency, and light pollution.
is clear that, although there are a variety of lighting technologies in use today, none is perfect. Many options still have a low efficiency, mainly in residential lighting and specialty lighting. Many efficient products should resign other factors as the quality of color and toxicity. Clearly there is need for further responses to the increasing demand for artificial light, as is the case with LEDs.
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