LED Lighting

Health concerns about LED streetlights Exposure to the light of white LED bulbs suppresses melatonin by up to five times more than exposure to the light of pressure sodium bulbs. The fact that white light, emitting at wavelengths of 400-500 nanometers suppresses the production of melatonin produced by the pineal gland is known. The effect is disruption of a human being’s biological clock resulting in poor sleeping and rest periods. Research at the University of Madrid Complutense University has claimed that long term exposure to LED Street-lighting can cause irreparable harm to the retina of the human eye. The Madrid study said this was caused by the high level of radiation in the’’blue band’’ Artificial night-time lighting has various effects on humans (not to mention wildlife) and exposure to optical radiation affects human physiology and behavior, both directly and indirectly. Many areas are not well understood,...

LED street light An LED street light (also referred to as LED road lighting) is an integrated light-emitting diode (LED) light fixture that is used for street lighting. Design and style Different designs have been created that incorporate various types of LEDs into a light fixture. The current trend is to use high power 1 watt LEDs. However, some companies use low power LEDs in their products, including several low power LEDs packed together to perform the same purpose as a single high power LED. The shape of the LED street light depends on several factors, including LED configuration, the heat sink used with the LEDs and aesthetic design preference.An LED street light is an integrated light that uses light emitting diodes (LED) as its light source. These are considered integrated lights because, in most cases, the luminaire and the fixture are not separate parts (except LEDGine-based luminaires). New in manufacturing...

Limitations Many will not work with existing dimmer switches designed for [higher power] incandescent lamps. Color rendering is not identical to incandescent lamps which emit close to perfect Black-body radiation as that from the sun and for what eyes have evolved. A measurement unit called CRI is used to express how the light source's ability to render the eight color sample chips compare to a reference on a scale from 0 to 100. LEDs with CRI below 75 are not recommended for use in indoor lighting. LED lamps may flicker. The effect can be seen on a slow motion video of such a lamp. The extent of flicker is based on the quality of the DC power supply built into the lamp structure, usually located in the lamp base. Longer exposures to flickering light contribute to headaches and eye strain. LED efficiency and life span drop at higher temperatures, which limits the power that can be used in lamps that physically replace existing filament and com...

Comparison table Cost Comparison for 60 watt incandescent equivalent light bulb (U.S. residential electricity prices) Incandescent Halogen CFL LED (EcoSmart clear) LED (Philips) LED (Cree) Purchase price $0.41 $1.17 $0.99 $3.66 $1.50 $4.99 Watts 60 43 14 6.5 8.5 9.5 lumens (mean) 860 750 775 800 800 815 lumens/watt 14.3 17.4 55.4 123.1 94.1 85.8 Color Temperature kelvin 2700 2920 2700 2700 2700 2700 CRI 100 100 82 80 80 85 Lifespan (hours) 1,000 1,000 10,000 15,000 10,000 25,000 Lamp lifetime in years @ 6 hours/day 0.46 0.46 4.6 6.8 4.6 11.4 Energy cost over 20 years @ 11 cents/kWh $289 $207 $67 $31 $41 $46 Total cost over 20 years $307 $259 $70 $42 $48 $56 Total cost per 860 lumens $307 $297 $78 $45 $52 $59 Comparison based on 6 hours use per day (43,800 hours over 20 yrs) Energy Star qualification Reduces energy costs — uses at least 75% less energy than incandescent lighting, saving on operating expenses. Reduces maintenance costs...

Specialty uses Comparison to other lighting technologiesWhite Led   lamps have achieved market dominance in applications where high efficiency is important at low power levels. Some of these applications include flashlights, solar-powered garden or walkway lights, and bicycle lights. Monochromatic (colored) LED lamps are now commercially used for traffic signal lamps, where the ability to emit bright monochromatic light is a desired feature, and in strings of holiday lights. LED automotive lamps are widely used for their long life and small size (allowing for multiple bulbs), improving road safety. LED lamps are also becoming popular in homes, especially for bathroom and medicine cabinet lighting. See luminous efficacy for an efficiency chart comparing various technologies. Incandescent lamps (light bulbs) generate light by passing electric current through a resistive filament, thereby heating the filament to a very high temperatu...

Household LED lamps Replacement for existing lighting LED lamps are made of arrays of SMD modules that replace incandescent or compact fluorescent lamps, mostly replacing incandescent lamps rated from 5 to 60 watts. Such lamps are made with standard lamp connections and shapes, such as an Edison screw base, an MR16 shape with a bi-pin base, or a GU5.3 (bi-pin cap) or GU10 (bayonet fitting) and are made compatible with the voltage supplied to the sockets. They include driver circuitry to rectify the AC power and convert the voltage to an appropriate value, usually a switched-mode power supply.Lamp sizes and bases As of 2010 some LED lamps replaced higher wattage bulbs; for example, one manufacturer claimed a 16-watt LED lamp was as bright as a 150 W halogen lamp A standard general-purpose incandescent bulb emits light at an efficiency of about 14 to 17 lumens/W depending on its size an...

Household LED lamps Replacement for existing lighting Main article: LED tubeLED tube lamps Lighting designed for LEDs LED lamps are made of arrays of SMD modules that replace incandescent or compact fluorescent lamps, mostly replacing incandescent lamps rated from 5 to 60 watts. Such lamps are made with standard lamp connections and shapes, such as an Edison screw base, an MR16 shape with a bi-pin base, or a GU5.3 (bi-pin cap) or GU10 (bayonet fitting) and are made compatible with the voltage supplied to the sockets. They include driver circuitry to rectify the AC power and convert the voltage to an appropriate value, usually a switched-mode power supply.Lamp sizes and bases As of 2010 some LED lamps replaced higher wattage bulbs; for example, one manufacturer claimed a 16-watt LED lamp was as bright as a 150 W halogen lamp A standard general-purpose incandescent bulb emits light at...

Examples of early adoption In 2009 the exceptionally large Christmas tree standing in front of the Turku Cathedral in Finland was hung with 710 LED lamps, each using 2 watts. It has been calculated that these LED lamps paid for themselves in three and a half years, even though the lights run for only 48 days per year.In 2008 Sentry Equipment Corporation in Oconomowoc, Wisconsin, US, was able to light its new factory interior and exterior almost solely with LEDs. Initial cost was three times that of a traditional mix of incandescent and fluorescent lamps, but the extra cost was recovered within two years via electricity savings, and the lamps should not need replacing for 20 years. In 2009 the Manapakkam, Chennai office of the Indian IT company, iGate, spent ₹3,700,000 (US$80,000) to light 57,000 sq ft (5,300 m 2 ) of office space with LEDs. The firm expected the new lighting to pay for itself fully within 5 years. ...

History Before electric lighting became common in the early 20th century, people used candles, gas lights, oil lamps, and fires. Humphry Davy developed the first incandescent light in 1802, followed by the first practical electric arc light in 1806 By the 1870s, Davy's arc lamp had been successfully commercialized, and was used to light many public spaces. The development of a steadily glowing filament suitable for interior lighting took longer, but by the early twentieth century inventors had successfully developed options, replacing the arc light with incandescent lights. The first LEDs were developed in the early 1960s, however, they were low-powered and only produced light in the low, red frequencies of the spectrum. The first high-brightness blue LED was demonstrated by Shuji Nakamura of Nichia Corporation in 1994.The existence of blue LEDs and high-efficiency LEDs led to the development of the first 'white LED', which employed a phosphor...

 LED lamp An LED lamp is a light-emitting diode (LED) product which is assembled into a lamp (or light bulb) for use in lighting fixtures. LED lamps have a lifespan and electrical efficiency which are several times greater than incandescent lamps, and are significantly more efficient than most fluorescent lamps, with some chips able to emit more than 300 lumens per watt (as claimed by Cree and some other LED manufacturers). The LED lamp market is projected to grow by more than twelve-fold over the next decade, from $2 billion in the beginning of 2014 to $25 billion in 2023, a compound annual growth rate (CAGR) of 25%. As of 2016, LEDs use only about 10% of the energy an incandescent lamp requires. Like incandescent lamps and unlike most fluorescent lamps (e.g. tubes and compact fluorescent lamps or CFLs), LEDs come to full brightness without need for a warm-up time; the li...