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					LED display, and the difference between LCD and LED
LED display (LED panel):
LED is light emitting diode, LED abbreviation. It is a semiconductor light-emitting
diode by controlling the display to display text, graphics, images, animations, quotes,
video, video signals and other information on the display screen.

LED technology advances and applications to expand the market demand, the greatest
driving force. Initially, LED mini light only as the computer, audio and video
recorders and other high-equipment applications, with large scale integrated circuit
and computer technology advances, LED displays are rapidly rising in recent years
gradually extended to securities market Gupiao machine digital cameras, PDA and
mobile phones.

LED display set microelectronics, computer technology, information processing in
one, with its colorful, wide dynamic range, high brightness, long life, stable and
reliable, to become the most advantage of the new generation of display media, and
now, LED display has been widely used in large squares, commercial advertising,
sports venues, information dissemination, press releases, securities trading, to meet
the needs of different environments.

LED display structure and classification

LED chip through the proper connections (including serial and parallel) and
appropriate optical structure. May constitute a light emitting display light-emitting
section or point. Paragraph or by light emitting point can be composed of digital
control, sign control, rice word tube, matrix management, management- level monitors,
etc.. Usually digital tube, pipe symbols, strokes, said a total of m characters tube
monitor, but the stroke display and matrix management collectively referred to as
character display.

(A) LED display structure

Basic semiconductor digital tube LED strip from the seven chip according to Figure
12 arranged in the. Enables the display of 0 to 9. The specific structure of the
"reflector-type",                     "seven-segment
bar-style" and "monolithic integrated a number of
digital" and so on

(1) reflector-type digital pipe usually made of plastic with a white seven-segment type
with a resonant reflector shell, a single LED and reflector affixed to the seven
reflection cavity with each other on bits of printed circuit board, the bottom of each
reflector The center is the LED chip. Loaded reflector in front, with the pressure
welding method in the corresponding chip and printed circuit metal strips with good
φ30μm between the aluminum line or metal wire, the reflector instillation in epoxy
resin, then the printed circuit board with chips alignment with the reflector plate
bonding, and curing.

Reflector-type digital control of packages and the actual closure of two free seal. Seal
means real scattering agents and dyes used epoxy resin, used for one or more two-bit
device. Air sealing approach is covered in the top of the filter film and the absorption
of light film, to improve the reliability of the device must be in the chips and the base
plate coated with a transparent insulating plastic, which also can increase the light
efficiency. This approach is generally used for more than four figures (or the symbol
display).

(2) strip seven-segment type is a mixed package of digital control. It is to do or die of
gallium phosphide GaP wafer, designated as containing only one or several LED light
bar, and then glued to the same seven day glyph "Kovar" box,
and with the bonding process within the lead with a good, and the n epoxy
encapsulation up.

(3) The number of single-chip integrated LED digital display in the substrate material
(large wafer), using integrated circuit technology to produce a large number of
seven-segment digital display graphics chips by dicing to elect qualified, on the bit
attached to the printed circuit board, with the pressure welding process leads to lead,
and then top it up with "fish-eye lens" shell. They apply to a
small number of instruments in the.

(4) symbol control, rice production of the word control means and digital control
similar.

(5) matrix control (light-emitting diode dot matrix) also can be used similar to the
monolithic integrated approach produced a number of digital display technology.

(B) LED Display Categories

(1) high marks by the word: character strokes display a high minimum 1mm
(monolithic integrated high number of digital control word is generally 2 ~ 3mm).
Other types of strokes display up to 12.7mm (0.5 inches) or even hundreds of mm.

(2) divided by the color red, orange, yellow, green and a few species.

(3) The structure of points, there are reflector-type, single and monolithic integrated
seven-segment type.

(4) from the light-emitting section of electrode connection points are two common
anode and common cathode.
(C) LED display of parameters

As the LED display is LED-based, so it's light, electrical characteristics
and the ultimate meaning of the parameters most of the same light-emitting diodes.
However, LED display includes multiple light-emitting diode, so take the following
specific parameters:

1. Luminous intensity ratio

As the digital pipe sections in the same drive voltage, forward current of different
sections, so sections of intensity. All segments of the luminous intensity value of the
ratio of maximum to minimum ratio of luminous intensity. Ratio can be 1.5 to 2.3, the
maximum not more than 2.5.

2. Pulse Forward Current

If the pen display each piece of work typical DC forward current IF, in the p ulse, the
forward current can be much larger than IF. The smaller the pulse duty cycle, pulse
forward current can be greater.
The difference between LED and LCD
LED displays and LCD monitors compared to, LED brightness, power consumption,
viewing angle and the refresh rate and so on, have more advantages. LED and LCD
power consumption ratio is about 1:10, and a higher refresh rate makes the LED in the
video have better performance, can provide extremely wide 160 ° angle of view, can
display text, numbers, color images and animation information can also be broadcast
television, video, VCD, DVD and other color video signal, pieces of display can also
be broadcast networking. Organic LED display is the LCD response speed of the
individual elements of LCD screen 1000 times in the bright light can not stop
watching, and adapt to the low temperature of 40 degrees below zero. Using LED
technology, can produce thinner than the LCD, brighter, clearer displays with a wide
range of applications.

LCD is liquid crystal display of the name: it includes a TFT, UFB, TFD, STN and
other types of liquid crystal display.

Commonly used in notebook LCD screen is TFT. TFT screen is thin film transistor,
the English full name (ThinFilmTransistor), is an active matrix type liq uid crystal
display, set back in its special fluorescent tubes, can take the initiative on the screen to
control each pixel independently, which is called the origin of active matrix TFT This
can be greatly improved response time, about 80 milliseconds, while the STN for 200
milliseconds! also improved the STN flashing (water wave) blurred, effectively
improve the ability of playing the dynamic images, and compared with STN , TFT has
excellent color saturation, reducing power and higher contrast, the sun st ill see very
clearly, but the drawback is more power and higher cost.
Simply put, LCD and LED are two different display technologies, LCD is composed
of liquid crystal displays, and LED light-emitting diode is formed by the display. LED
displays and LCD monitors compared to, LED brightness, power consumption,
viewing angle and the refresh rate and so on, have more advantages.

				
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posted:9/1/2010
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