LCD professional knowledge
Author:13418898006 Time:2021-07-20 16:52 Browse(987)
Liquid crystal display (LCD)
The working principle of liquid crystal display (LCD) is totally different from that of traditional CRT.
its most basic display component is liquid crystal material.

LCD professional knowledge

in short, liquid crystal display is a layer (or multi-layer) of liquid crystal material sandwiched between two pieces of glass.
there are several light tubes behind the glass, and the liquid crystal material changes its light transmission state under signal control, In this way, you can see the image in front of the glass panel.
the performance of an LCD is determined by the following aspects:
response time.
the speed of response time is an important indicator to measure the quality of the LCD.
response time refers to the response speed of the LCD to the input signal, Generally speaking, it can be divided into two parts: tr (rise time) and TF (fall time).
the response time refers to the sum of the two. The smaller the response time, the better. If the response time exceeds 40 ms, the better, At present, most of the standard response time of LCD is about 25 ms.
however, there are a few models that can achieve 16 Ms.
with 16 ms super fast response time,
it can display more than 60 frames per second, which completely solves the problems of dragging shadow, noise and so on when traditional LCD is playing games or watching DVD
contrast refers to the brightness ratio of the bright area to the dark area of the display under the specified lighting conditions and observation conditions.
contrast is a parameter that directly reflects whether the LCD can reflect the rich color scale.
The higher the contrast, the better the level of the restored image.
at present, the nominal value of LCD is 250:1 or 300:1.
for high-end products, 400:1 or 500:1.
it should be noted that.
the contrast must match the brightness to produce the best display effect.
the high contrast of 400:1 or 500:1 will make the displayed image more bright.
the image is softer, The brightness of LCD is generally higher than that of traditional CRT.
the brightness of LCD is generally measured in CD / m2 (lumen per square meter). The higher the brightness, the stronger the anti-interference ability of LCD to the surrounding environment, The display effect is more bright.
this parameter should be at least 200cd / m2.
it is better to be above 250cd / m2.
the higher the brightness of traditional CRT display is.
the greater its radiation is, and the brightness of liquid crystal display is obtained through the backlight of fluorescent tube, So there is no negative impact on the human body.
bad spots on the screen.
the most common bad spots on the screen are white spots or black spots.
the identification method of black spots is to turn the whole screen into a white screen.
then the black spots have no place to hide; The white dot is just the opposite. If the screen is turned to black, the white dot will show its original shape.
generally, the display with no more than 3 bad spots is considered qualified.
therefore, when purchasing LCD, users must pay attention to selecting products without bad spots.
if there are no white spots and black spots.
then they can only choose big brands with guaranteed quality.
the product quality is good
viewing angle.
LCD belongs to backlight display device.
the light emitted by the backlight behind the LCD module is provided by the backlight, which inevitably leads to the LCD has only one best viewing angle - emmetropia.
when you view from other angles.
because the backlight can penetrate the adjacent pixels and enter the human eye, it will cause color distortion, The range of non distortion is the viewing angle of the LCD.
the viewing angle of the LCD can be divided into horizontal viewing angle and vertical viewing angle.
the horizontal viewing angle is generally larger than the vertical viewing angle.
at present.
as long as the horizontal viewing angle reaches 120 degrees, When the vertical viewing angle reaches 140 degrees, it can meet the application requirements of most users.
the latest LCD panel is produced with wide viewing angle technology.
it can reach 140 degrees up and down and 150 degrees left and right, However, it is more than enough for most applications.
dot distance.
the dot distance of LCD refers to the space between each pixel of LCD.
at present, the mainstream 15 inch LCD displays The standard point distance of display products is generally 0.297mm, and the corresponding resolution is 1024 × 768.
the visible area of liquid crystal display is "real.
generally, there is a reference: the visible area of 15 inch liquid crystal display is close to that of 17 inch CRT display.
the visible area of 15 inch liquid crystal display is 304.1 x 228.1 (mm).
the visible area of 15 inch liquid crystal display is close to that of 17 inch CRT display
the bandwidth of liquid crystal display is also an index to measure liquid crystal display.
generally, the bandwidth of liquid crystal display is 80MHz.
large screen liquid crystal display has the advantages of both liquid crystal display and large screen display.
the large screen liquid crystal display products represented by 17 inch liquid crystal display have been widely welcomed by consumers In addition,
its visible area is larger than that of 18 inch color TV, and it has the advantage of non radiation, which enables users to appreciate it in close range.
because the panel thickness of LCD itself is the same.
in other words, the main factors affecting the thickness of LCD will be the technology of circuit controller, the design of plastic shell, the thickness of LCD panel The interior space is compressed.
of course.
a lot of advanced liquid crystal technology is integrated, the latest ultra-thin liquid crystal panel and thinner high brightness cold cathode fluorescent lamp are adopted, and the more integrated control IC design and more optimized heat dissipation treatment can also achieve the purpose of reducing the overall size.
in a word.
the liquid crystal display realizes the true plane, ultra-thin body, low temperature and high brightness cold cathode fluorescent lamp Low voltage, low power consumption, low radiation, light weight, small size, no flicker, reduce visual fatigue, green environmental protection, good for human health and other reasons have won the favor of more and more computer lovers.
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