Characteristics of the led light source

1. Characteristics of the LED light source
Voltage
LED low voltage power supply, power supply voltage between 6-24V, depending on the product,
so it is safer than the use of high-voltage power supply power supply, particularly in public places.
Efficacy
Energy consumption reduced by 80% than the same luminous efficiency of incandescent
Applicability
Very small, small piece of each unit LED is 3-5mm square, so the device can be fabricated into
various shapes, and is suitable for the environment variable
Light-emitting diodes
Stability
100,000 hours, the light fades to 50% of the initial
Response time
Incandescent response time of milliseconds, the response time of the LED lights for a nanosecond
Of environmental pollution
No harmful metallic mercury
Color
Materials of light-emitting diodes by chemical modification methods, adjusting the energy band
structure and band gap, red yellow blue orange multicolor light. Red tube voltage is small,
different colors of red, orange, yellow, green, and blue light-emitting diode operating voltage is
increased successively.
Price
LED price is now more and more civilians, due to the LED power-saving features, perhaps in the
near future, people are the incandescent LED lights. Now, some cities in our country roads,
schools, factory and other places have switched to the the Wan LED street light, energy-saving
lamps.

2. Monochromatic LED types and history of the development
The LED light source made of the earliest applications of semiconductor PN junction
light-emitting principle is introduced in the early 1960s. Use at the time material is GaAsP, red (λp
= 650nm), the drive current of 20 mA, the luminous flux is only thousandths of a few lumens,
luminous efficiency of about 0.1 lm / W
The mid-1970s, the introduction of elements of In and N, generated by the LED green (λp =
555nm), yellow (λp = 590nm) and orange (λp = 610nm), luminous efficiency is also increased to a
lumens / watt.
To the early 1980s, there has been a GaAlAs LED light source, the red LED luminous efficiency of
10 lumens / watt.
The early 1990s, of red, yellow the GaAlInP and green, blue GaInN two new materials successfully
developed, so that the LED luminous efficiency has been greatly improved. In 2000, the former is
made of LED in red, orange District (λp = 615nm) light efficiency of 100 lm / W, while the latter is
made of LED luminous efficiency in the green region (λ p = 530nm) can reach 50 lm / watts.
Monochromatic LED applications
Light-emitting diodes
The initial LED as the light of the instructions of the instrumentation, then a variety of
light-colored LEDs in traffic lights and a large area display a wide range of applications, resulting
in a good economic and social benefits. To 12 inches of red traffic lights, for example, in the
United States was long-lived, low-efficiency 140-watt incandescent lamp as a light source, it
produces 2000 lumens of white light. The red filter, the light loss of 90%, leaving only 200 lumens
of red light. In the light of the new design, Lumileds uses 18 red LED light source, including circuit
losses, the total power consumption of 14 watts to produce the same luminous efficiency.
The car lights are also an important area of the LED light source applications. 1987, China began
to be installed in the car CHMSL LED response speed (nanosecond), an early stage so that the
trailing vehicle drivers know that driving conditions to reduce rear-end accidents.

3. In addition, LED lights in the outdoor red, green, blue full-color display, mini flashlight key chain
field have been applied.
Resourse from electronics store