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