Composition of LCD panel
Author:Guo zhaoxun Time:2021-07-19 13:34 Browse(90)
Liquid crystal display (LCD) is called liquid in English
the English full name of liquid crystal display (LCD) is liquid crystal display.
it is a kind of display that uses liquid crystal to control light transmittance technology to realize color.
compared with CRT display.
the advantages of LCD are obvious.
because light and dark are controlled by controlling light transmittance.
when the color remains unchanged, the liquid crystal also remains unchanged, In this way, there is no need to consider the problem of refresh rate.
for LCD with stable picture and no flicker sense,
the refresh rate is not high, but the image is also very stable.
LCD also uses the technology principle of liquid crystal to control the light transmittance to make the bottom board glow as a whole.
therefore, it achieves the real full plane.
some high-end digital LCD displays use digital mode to transmit data, display the light, and display the light The image is displayed.
in this way, there will be no color deviation or loss caused by the graphics card.
there is no advantage of radiation at all.
even if you watch the LCD screen for a long time, it will not cause great damage to your eyes.
it is small in size and easy to use The low power consumption of a 15 inch LCD is one third of that of a 17 inch flat CRT.
at present, compared with CRT, the image quality of LCD is still not perfect.
the color performance and saturation of LCD display are different to CRT display.
moreover, the response time of LCD display is shorter It is also longer than CRT, and can be used when the picture is still. Once it is used to play games and watch video discs, the weakness of LCD will be exposed, and the picture delay will lead to ghosting, tail off and other phenomena, which will seriously affect the display quality.
in this paper, the development of LCD is introduced
working principle of LCD: from the perspective of LCD structure.
whether it is laptop or desktop system, the LCD screen is a layered structure composed of different parts.
LCD is composed of two glass plates.
the thickness is about 1 mm, between which is a 5-layer structure containing liquid crystal material μ Because the liquid crystal material itself does not emit light.
there are light tubes as light sources on both sides of the display screen. On the back of the liquid crystal display screen, there is a backlight plate (or uniform plate) and a reflective film. The backlight plate is composed of fluorescent materials, which can emit light lines, Its main function is to provide a uniform background light source.
the light from the backlight enters the liquid crystal layer containing thousands of liquid crystal droplets after passing through the first layer of polarization filter layer.
the droplets in the liquid crystal layer are contained in a small cell structure.
one or more cells constitute a pixel on the screen.
it is transparent between the glass plate and the liquid crystal material The electrodes are divided into rows and columns. At the intersection of rows and columns, the rotation state of liquid crystal is changed by changing the voltage. The liquid crystal material acts like a small light valve.
around the liquid crystal material are the control circuit and the driving circuit.
when the electric field is generated by the electrodes in the LCD.
the liquid crystal molecules will be distorted, So the light passing through it is refracted regularly, and then filtered by the second filter layer to be displayed on the screen.
there are also weaknesses and technical bottlenecks in LCD technology.
compared with CRT display, the brightness, picture uniformity, image quality, etc There is an obvious gap between the visual angle and the reaction time.
the reaction time and the visual angle depend on the quality of the liquid crystal panel.
there is an obvious gap between the visual angle and the reaction timeThe picture uniformity is closely related to the auxiliary optical module.
for liquid crystal display, the brightness is often related to its back light source.
the brighter the back light source is.
the brightness of the whole liquid crystal display will also be improved.
in the early liquid crystal display, because only two cold light sources are used, the brightness is often uneven, At the same time, the brightness was not satisfactory.
it was not until the introduction of four cold light source lamps.
it was greatly improved.
the signal response time is the response delay of the liquid crystal unit of the liquid crystal display.
in fact, it refers to the time required for the liquid crystal unit to change from one kind of molecular arrangement state to another.
the smaller the response time, the better Well, it reflects the speed of the LCD pixels responding to the input signal, that is, the speed of the screen changing from dark to light or from light to dark.
the smaller the response time is, the user will not have the feeling of tail dragging when looking at the moving picture.
some manufacturers will reduce the concentration of conductive ions in the LCD to achieve the rapid response of the signal.
however, the color saturation, brightness, color saturation and color saturation of the LCD will be reduced The contrast will decrease accordingly, However, the display effect of LCD is sacrificed.
some manufacturers add an IC image output control chip to the display circuit.
the IC chip can process the display signal specially.
the IC chip can adjust the signal response time according to the VGA output signal frequency.
the IC chip can adjust the signal response time according to the VGA output signal frequency Because it does not change the physical properties of the liquid crystal.
therefore, it has no effect on its brightness, contrast and color saturation,The manufacturing cost of this method is relatively high.
it can be seen from the above.
the quality of liquid crystal panel can not fully represent the quality of liquid crystal display. No matter how good the panel is, it can not make excellent liquid crystal display without excellent display circuit cooperation.
with the increase of LCD product output, the quality of liquid crystal panel can be improved The cost of LCD will be reduced.
LCD will be widely used.
classification of LCD.
common LCD can be divided into four types according to physical structure:
twisted nematic; TN twisted nematic
super twisted nematic (STN super TN)
DSTN dual scan torsion nomograph<
thin film transistor (TFT thin film transistor).
TN is the most basic display technology in LCD.
and other types of LCD are improved based on TN.
its operation principle is simpler than other technologies.
please refer to the picture below.
the figure shows the characteristics of TN LCD The display principle of STN is similar to that of TN.
the difference is.
the liquid crystal molecules of TN twist nematic field effect rotate the incident light by 90 degrees, while the STN super twist nematic field effect rotates the incident light by 180-270 degrees.
the display principle of STN type is similar to that of TN
DSTN scans twisted nematic liquid crystal display by double scanning.
to achieve the purpose of display.
DSTN is developed from super twisted nematic display (STN).
because DSTN adopts double scanning technology.
therefore, the display effect is greatly improved compared with STN.
TFT type liquid crystal display is more complex.
it is mainly composed of: fluorescent tube, light source, light source, light source and so on Light guide plate, polarizing plate, filter plate, glass substrate, alignment film, liquid crystal material, thin mode transistor, etc.
first of all.
liquid crystal display must use backlight, that is, fluorescent tube to project light source, These light sources will first pass through a polarizing plate, and then through the liquid crystal.
at this time, the arrangement of liquid crystal molecules will change the angle of light passing through the liquid crystal.
then these light must pass through the front color filter film and another polarizing plate.
therefore, we can control the final light intensity and color just by changing the voltage value on the liquid crystal.
in this way, we can control the light intensity and color The color combinations with different hues are changed on the LCD panel.
it is the panel of the mainstream LCD at present.
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