2. HOW ARE WHITE LEDS CREATED?
3. What the range of color temperatures of WLED is?
4. What Color Rendering Index (CRI) of LED is?
5. What is the advantage of LED?
There are currently two ways to make white light with LEDs. One method mixes multiple wavelengths of different LEDs to make white light (i.e. RGB); allowing the lighting designer to tune the white light to a specific color temperature. The second method uses a blue Indium-Gallium-Nitride (InGaN) LED with a phosphor coating to create white light. This is the method that results in the more commonly seen “white LED”.
There are currently two ways to make white light with LEDs. One method mixes multiple wavelengths of different LEDs to make white light (i.e. RGB); allowing the lighting designer to tune the white light to a specific color temperature.
The second method uses a blue Indium-Gallium-Nitride (InGaN) LED with a phosphor coating to create white light. This is the method that results in the more commonly seen “white LED”.
WLED covers the full spectrum from 2760K-10,000K. Generally, we offer three kinds of white light for our customer. They are warm-white(3000K-3500K), neutral-white(4000K-5500K) and cool-white(5500K-7500K).A special color temperature lighting can be made as customer instruction.
Color Rendering Index or CRI is the calculated rendered color of an object. The higher the CRI (based upon a 0-100 scale), the more natural the colors appear. Natural outdoor light has a CRI of 100. At current technology, CRI of LED is between 70 and 85.
Energy Efficiency
LEDs are highly efficient. The best modern available white LEDs (as of late 2007) produce about 60-90, Compare to 14-17.5 lumens per watt for standard "A19" 120 volt 60 to 100 watt incandescents, and typically 16 to 21 for most halogen lamps rated to last 2,000 hours or more.
Luminous efficacy is an important indicator of energy efficiency, but it doesn’t tell the whole story, particularly with regard to directional light sources. Due to the directional nature of their light emission, LEDs potentially have higher application efficiency than other light sources in certain lighting applications. Fluorescent and standard “bulb” shaped incandescent lamps emit light in all directions. Much of the light produced by the lamp is lost within the fixture, reabsorbed by the lamp, or escapes from the fixture in a direction that is not useful for the intended application. For many fixture types, including recessed downlights, troffers, and under-cabinet fixtures, it is not uncommon for 40-50% of the total light output of the lamp(s) to be lost before it exits the fixture. LEDs emit light in a specific direction, reducing the need for reflectors and diffusers that can trap light, so well-designed fixtures and systems using LEDs can potentially deliver light more efficiently to the intended location.
Some LEDs are projected to produce a long service life of about 100,000 hours. For this reason LEDs are ideal for hard-to-reach/maintain fixtures such as exit sign lighting and, combined with its durability, pathway lighting. This service life can be affected by the application and environmental factors, including heat and if being overdriven by the power supply.
Environmental ProtectionLEDs are made from non-toxic materials. Which unlike incandescent lamps waste too much energy, unlike fluorescent lamps consume high energy and produce toxic gases. and unlike neon as high-voltage requirements and easily damaged, which has been recognized as high-tech environmental protection products by global market. LEDs can also be recycled.
No UV Emissions/Little InfraredLEDs produce no UV radiation and little heat, making them ideal for illuminating objects, such as works of art, that are sensitive to UV light.
DurableLEDs are highly rugged. They feature no filament that can be damaged due to shock and vibrations. They are subject to heat, however, and being overdriven by the power supply.
Small Size/Design FlexibilityA single LED is very small and produces little light overall. However, this weakness is actually its strength. LEDs can be combined in any shape to produce desired lumen packages as the design goals and economics permit. In addition, LEDs can be considered miniature light fixtures; distribution of light can be controlled by the LEDs’ epoxy lens, simplifying the construction of architectural fixtures designed to utilize LEDs. A controller can be connected to an LED fixture to selectively dim individual LEDs, resulting in the dynamic control of distribution, light output and color. Finally, DC power enables the unit to be easily adaptable to different power supplies.
Other BenefitsThe other benefits of LEDs include:
·Lights instantly
·Can be easily dimmed
·Silent operation
·Low-voltage power supply (increased safety)
The high efficiency LEDs can be used in a variety of applications. The most appropriate solution is dependent on the overall budget, needs and type of installation. Different light sources will be used in different applications based on the needs of the people.
| Lamp Type | Incandescent | Compact Fluorescent | WLED |
| Efficiency (Lumens/Watt) | 5-18 | 30-79 | 40~90 |
| Rated Life (Hours) | 1,000 | 6,500 – 15,000 | 50,000 to 100,000 |
| Durability | Very fragile | Very fragile | Durable |
| Power consumption (Watt) | 5W | 7W | 2W |
| CCT deg K | 2,652 deg. | 4,200 deg | 5,000 deg |
| CRI | 98 | 62 | 82 |
| $ after 50,000 Hours | $175 | $131 | $20 |

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