LEDs light the future. Tiny and yet very efficient, LEDs are revolutionizing the world of lighting. Introduced in the market in the 60’s, LEDs are conquering more and more markets. We find them in street lighting, as lighting solution at our office and in our TV displays.
Their versatile usage is combined with highest efficiency. LEDs save a lot of energy and have an extremely long life time. EMD Performance Materials, as one of the leading manufactures, develops innovative phosphor materials for LEDs.
LED-Backlighting – for energy efficient ultra flat displays
LEDs are replacing the conventional cold cathode tubes of the backlight in liquid crystal displays. As a result white LED backlights enable the exquisite design of ultra flat LCDs which are about one third more efficient.
Light on demand – global and local dimming
LEDs enable new energy saving technologies such as local dimming. The light emitting diodes are arranged over the whole area behind the display and their luminance can be controlled in independent groups of LEDs. The advantage is that for every display segment only that amount of light is generated that is really needed. Therefore one can display very bright as well as very dark seg-ments efficiently with local dimming. This means only the really bright segments need to be supplied with a lot of light. This at the same time leads to improved image contrast. Local dimming however can only be used in TVs with direct backlighting.
Global dimming however can be used in TVs with conventional backlighting as well as Edge-LED TVs, where it also improves the image contrast. In Edge-LED TVs the LED are only positioned around the rim of the TV, which enables the ultra slim design.
LEDs – the shooting stars of lighting
In the domain of lighting too LEDs fully play out their advantages. The LED technology is recognized as one of the most important discoveries in the history of lighting, since Edison discovered the light bulb more than 100 years ago.
LEDs are very efficient light sources. Their high optical efficiency of more than 100 lm per Watt is combined with an extremely long lifespan. High performance LEDs last up to 50.000 hours and more. LEDs score on efficiency not only in the case of outdoor lighting they also provide special light quality for indoor lighting using intelligent controls. LEDs can be dimmed automatically if only very little or no light is required.
Brilliant color rendering
Thanks to continuously improved phosphors LEDs nowadays achieve a very good color rendering. The average color rendering index (CRI) Ra gives an indication how natural colors are reproduced in the light of a lamp. If the index is low, then the color rendering properties are bad. Ra=100 is the maximum value, where the colors are rendered perfectly. High performance LEDs come very close with values of 93 to 95 already. The light bulb, like sunlight reaches the maximum value CRI 100. Special fluorescent tubes have a range from 85 up to and above 90.
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