Frequently Asked Questions

What is LED?
      LED is a semiconductor device converting electric current directly into light emission. LED means Light Emitting Diode. LED consists of a semiconductor crystal on a substrate, body with the terminals and optical system. Modern LEDs poorly similar to the first hull LEDs which were used for indication.

1 - Plastic Lens
2 - Silicone Encapsulent
3 - InGaN Semiconductor Flip Chip
4 - Solder Connection
5 - Silicon Sub-mount Chip with ESD Protection
6 - Heatsink Slug
7 - Gold Wire
8 - Cathode Lead

What are the advantages of LEDs?
       In contrast to incandescent or fluorescent lamps, electric current in the LED is converted directly into light radiation and theoretically it can be done almost without loss. Indeed the LED (with proper heatsink) is heated a little that makes it indispensable for certain applications. In addition, LED emits in the narrow part of the spectrum, its color is pure, what is especially appreciated by designers, ultraviolet and infrared radiation, generally, are absent. LED is mechanically strong and extremely reliable, its durability can reach 100 000 hours, that is almost 100 times more than icandescent bulbs's, and 10 times more than fluorescent lamps's. Finally, the LED - a low-voltage electrical device, and therefore, it is safe.

How to get white light using LEDs?
       There are three ways to get white light from LEDs. The first is color mixing on RGB technology. Red, blue and green LEDs are densely placed on the one matrix, their emission is mixed with an optical system, such as lense. We have white light as a result. The second way is that three luminophors emitting blue, green and red lights respectively are placed on the LED's surface, which emits in the ultraviolet range (there are). This is similar to fluorescent lamp. And, finally, the third method is that yellow-green or green-red luminophor are placed on blue LED, so 2 or 3 emissions are mixed to form white or close to white light.

What are the electrical and optical characteristics of LEDs?
       LED – is a low-voltage device. Usual LED used for indication consumes from 2 to 4V DC voltage at a current of 50 mA. The LED used for illumination consumes the same voltage but higher current - from a few hundred mA to 1A in the draft. Separate LEDs in the LED module can be connected in series and the total voltage turns out higher (typically 12 or 24 V). Connecting LEDs it is necessary to observe polarity, otherwise the device may be damaged. Breakdown voltage is specified by manufacturer and usually is more than 5V for single LED. LED brightness is characterized by luminous flux and axial light force and also by orientation diagram. Current LEDs of different structures emit in the solid angle from 4 to 140 degrees. Color, as usual, is determined by chromaticity coordinates and color temperature, and also emission wavelength. To compare the efficiency of LEDs with each other and with other light sources light output is used: the luminous flux per watt of electrical power. The price of 1 Lumen is interesting marketing characteristic also.

Why is it necessary to stabilize current through the LED?
       Currents depends exponentially on voltage in operational modes, so slight voltage changes lead to great current changes. Because of the light output is directly proportional to the current, LED brightness is unstable. So it is necessary to stabilize the current. In addition, if the current exceeds allowed limit, overheating of LED can lead to its accelerated aging.

Is it possible to adjust the brightness of the LED?
       LED brightness can be regulated very well, not by reducing the supply voltage - this is just what you shouldn't do – but by so-called PWM method of pulse-width modulation, which requires special control block (actually, it can be combined with the power block and converter as well as with color management controller of RGB-matrix). PWM method consists in that the LED is supplied by pulse-modulated current, not by direct current, at that the signal frequency should be hundreds or thousands of hertz, while the width of pulses and pauses between them may vary. Average LED brightness becomes controllable, at the same time the LED doesn't go out. Slight change in color temperature of LED with dimming is incomparable with the same shift for light bulbs.

What does determine the service life of LEDs?
       LEDs are considered to be extremely durable, but is not completely so. The higher current is passed through the LED during his service, the higher the temperature, the faster the aging occurs. That's why the life of a high-power LEDs is shorter than that of low-power signal LEDs, and it is currently 20 - 50 thousand hours. Aging is expressed primarily in the reduction of brightness. When the brightness reduced on 30% or half the LED should be changed.

The using of LED's isn't harmful for human eyes, so is it or not?
       Emission spectrum of LEDs is close to the monochromatic, it's radical difference from the spectrum of the sun or incandescent lamps. Is it good or bad – it is not known, because there were no serious research in this field anywhere. There is no information about the harmful effects of LEDs on the human eye. It is hoped that the influence of LEDs on vision will be learned thoroughly at soon.

Where today is advisable to use LED products?
       LED products are used almost in all areas of lighting engineering, are essential in design lighting due to their pure color, as well as in dynamic lighting systems. They are favourable for applying where it's frequent maintenance is expensive, where it is hard necessary to save electricity, and where demands on electrical safety are high.