LED devices is often not used alone. As the indicator of the instrument may be only a single LED. As long as the LED is normally lit on the line. But as the lighting, display a backlight, it often requires a lot of LED devices together. Then choose LED devices based on usage.
Multiple devices together. Generally should consider the following questions: the case of multiple LED combination, we must consider whether the same as when the LED forward voltage drop at 20mA current. If they can use the parallel drive, if they are different tandem drive.
In combination with white LED light source, you must pay attention to the choice of indicators of several parameters: the color temperature uniformity: the white color temperature from greater than 2500 K-until more than 13 000 K. If the color temperature difference between the LED combination use, the visual effect of a certain bad too much. The general experience is different in more than 10 000 K, the color temperature of each LED color temperature difference can be between 1000K, so that the eye area too close to the color temperature. Low color temperature (less than 6,000 K) LED color temperature difference can not be larger than 500K. This combination can make the visual effects.
White LED light source used in shopping malls, discos, theater or show colors, be sure to choose high color rendering index. General lighting use color rendering index of 80 or more must be used in the above-mentioned occasions the color rendering index should be higher, preferably greater than 90, or at the mall to see the object colors and see objects in the sunlight, the color difference between the too big.
In combination with multiple LED light source, but also consider the uniformity of the light source. If the wavelength of living between 500 - 600 nm, light intensity difference of a few dozen mcd, the naked eye may see uneven brightness.
In combination with multiple LED light source and pay attention to the wavelength of each LED light source. Generally between 500 to 600 nm as long as the difference of 3 nm, the naked eye will be observed color is not the same as the other bands may be 3-5 nm, will detect color is not the same.
If you use the LED as a display, because the concept of distance farther, then LED wish angle and perspective of each LED is basically the same (a difference of ± 3. Or less), otherwi se will be seen by the naked eye brightness inconsistent .
As the LED backlight at the same distance, spot uniformity, and the spot size of ~ kind, and the angle of the LED devices. So the brightness will be uniform.
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