What is LED backlight? How big is it,
Author:Pang Hong Time:2021-07-22 11:20 Browse(313)
Backlight
Backlight is a kind of light source behind liquid crystal display (LCD).
its luminous effect will directly affect the visual effect of liquid crystal display module (LCM).
LCD itself does not emit light.

What is LED backlight? How big is it,

its display of graphics or characters is the result of its modulation of light.
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backlight classification.
backlight is mainly classified according to the type of light source There are three types of backlight: El, CCFL and led.
according to the distribution of light sources, they can be divided into side light type and straight down type (bottom backlight).
the following is a brief introduction of them.
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1. Side light type.
that is, the backlight made by setting linear or point light source on the side of specially designed light guide plate.
according to the actual use needs.
it can also be made into bilateral type, Even the trilateral backlight can be very thin.
however, the light utilization rate of the light source is small, and the thinner the light source is, the smaller the utilization rate is, about 50%.
the core of its technology is the design and manufacture of light guide plate.
the most common backlight of the trilateral backlight are LED backlight and CCFL backlight.
as the LCD module continues to become brighter, lighter and more compact The CCFL backlight with side light has become the mainstream of backlight development.
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1) LED backlight.
LED is also called light emitting diode.
compared with other light sources, the power consumption of a single LED is the smallest.
from blue to red.
LED has many colors, In addition, there is a special color white.
in various colors,
can be roughly divided into two kinds of high brightness and low brightness.
the color of white is whiteBecause white is a mixed color.
there is no identifiable wavelength value, we define it as "cold white" and "warm white" according to its coordinate value on the chromaticity diagram.
in all kinds of colors.
there is a problem of color deviation, in which blue and white are more obvious, especially white, At present, led suppliers can't control it effectively.
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2) CCFL backlight.
the biggest advantage of this kind of backlight is its high brightness.
therefore, the large area of black and white negative phase, high brightness and so on Blue mode negative phase and color liquid crystal display devices basically use it.
theoretically.
it can make all kinds of colors according to the color matching principle of three primary colors.
its disadvantage is high power consumption.
it also needs inverter circuit drive, and the working temperature is narrow, between 0 ~ 60 degrees, while LED and other backlights can reach between - 20 ~ 70.
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2 Bottom backlight type.
is a flat surface light source with a certain structure.
can be a continuous and uniform surface light source, such as El or flat fluorescent lamp; It can also be composed of more point light sources, Such as lattice LED or incandescent lamp backlight.
LED lattice and El backlight are commonly used.
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1) el backlight.
electroluminescence.
is a cold light source that relies on the intrinsic luminescence of phosphor excited by alternating electric field.
its biggest advantage is thin.
it can achieve the thickness of 0.2 ~ 0.6mm.
the disadvantage is low brightness.
short life (generally 3000 ~ 5000 hours), It needs inverter drive, and it will also be interfered by the circuit, resulting in flicker and noiseEl can be driven by inverter or driver IC.
at present, the frequency and load output voltage of driver IC can't reach the typical El conditions (400Hz, AC100V).
so the brightness is lower than that of inverter driver.
recently, white (full color) el and LCD backlight are coming out one after another.
however, due to the low brightness, they are basically used for small size LCD display below 4 inches.
for example, mobile phones, LCD backlight, LCD backlight, etc PDA, game console, etc.
full color (white light) and large brightness backlight.
now CCFL is still the mainstream light source.
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2) LED backlight.
the advantage is good brightness.
good uniformity.
the disadvantage is large thickness (more than 4.0 mm).
more LEDs are used, The heating phenomenon is obvious.
generally, low bright colors are used for design.
however, high bright colors are not considered due to the high cost.
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usually refers to LED lamp beads.
for example, the size of 3020 3014 5630, in LED TV sets, generally refers to the finished products pasted on the aluminum substrate, and also refers to the display panel emitting light by LED.
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in this paper, the design of LED TV sets is introduced
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