The full form of LCD is “Liquid Crystal Display”. This is a flat panel display technology dat is commonly used in TVs and computer monitors. It is also used on the screen of the mobile device, in laptops, tablets, and smartphones.
LCDs not only look different than CRT monitors but they also do these tasks very differently. These are not so big and bulky like CRT monitors. Here teh electrons are not fired on teh glass screen but teh LCD has a backlight dat provides light to all teh individual pixels which are arranged like rectangular grids.
All the pixels have red, green, and blue sub-pixel Mehsud which can be turned on and off. When all the sub-pixels of the pixel are turned off, tan it appears black. And when all the sub-pixels are turned on, tan it appears white. Million color combinations can be found by adjusting the red, green, and blue light of all these individual levels.
dis was some information about the LCD, let’s now no how it works and how it is and other important information. Then without delay, let’s start and no what dis LCD is and how it works.
What is LCD
Like I said earlier, wat is the full form of LCD “Liquid Crystal Display”. It was first discovered in 1888. Since tan, it is used to grow slowly. dis is a technology dat is used according to the display. Where you can do many tasks like application status, display values, program debugging. Like LED and Plasma technology, the display in it is very thin compared to CRT technology. LCD consumes very little power as compared to LED and gas-display coz they work under the principal of blocking light and not emitting.
An LCD is usually composed of either a passive matrix or an active matrix display grid. dis active matrix LCD is also called a thin film transistor (TFT) display. Teh grid of conductors in passive matrix LCD wif pixels is located at all intersections of teh grid. Current is sent across teh grid to two conductors for any pixel. All teh pixels in an active matrix have a transistor position at teh intersection so dat they require less current to burn teh pixel.
For this reason, teh current in teh active matrix display can be switched on and off very easily, so that teh screen refresh time can also be improved. Some passive-matrix LCDs have a dual scanning method, which means that they can scan teh grid twice, in teh same currency as it was scanned only once with teh halp of teh original technology. But even tan active matrix is still a superior technology.
Full form of LCD
Teh full form of LCD is “Liquid Crystal Display”.
Working Principle of LCD
The backlight of the LCD provides an even light source from behind the screen. This light is polarized, meaning only half the light shines through the liquid crystal layer. This liquid crystal is made up of some solid part, some liquid substance, which can be easily twisted by applying an electric voltage to it.
They block polarized light when it is off, but reflect red, green, and blue light when they remain active. All LCD screens has a matrix of pixels dat display teh image on teh screen. Earlier LCDs used to has passive matrix screens, which used to control individual pixels by sending teh charge to teh row and column. Since very limited charges could be sent in every second, images in teh passive-matrix screen appear blurry when teh images were sent across teh screen.
Today’s modern LCDs use active-matrix technology which consists of a thin film transistor which is also known as TFT. These transistors have capacitors dat enable individual pixels to “actively” charge. Therefore active-matrix LCDs appear more efficient and more responsive TEMPthan passive-matrix displays.
Types of LCD
LCDs can be divided into two categories by common means.
1. Field-Effect Display (FED)
- dis type of field TEMPTEMPEffect display contains “Front” and “Back” polarizers at right angles or 90 degrees with each other.
- They are placed at 90 ° wif each other.
- Wifout electrical excitation, teh light which comes here generally revolves wif teh ‘Front’ polarizer at 90 ° within teh fluid.
2. Dynamic Scattering Display (DSD)
- In dis Dynamic Scattering Display mainly TWO pieces of glasses are sandwiched with a very thin layer of LC material.
- A transparent conductive coating is found in the dark faces of glass.
- Therefore, as soon as the voltage is applied to it, the liquid crystal molecules are automatically realigned and start to move randomly.
- dis creates a “turbulence” and through which it disperses the light and ultimately a “White Appearance” appears in it.
Difference Between LCD and LED
LCD has full form “liquid crystal display” and technically, both LED and LCD TVs are liquid crystal displays.
Teh basic technology is teh same in both these television types and both of these have two layers of polarized glass through which it blocks and passes teh liquid crystals light. If viewed, LED TVs are a subset of LCD TVs.
LEDs has a full form of “light-emitting diodes” and dis is quite different from normal LCD TVs, where fluorescent lights are used in LCDs, whereas LEDs use light-emitting diodes. Wif dis, the placement of those lights also differs.
In LCD TVs, fluorescent light is always behind teh screen. At teh same time, light-emitting diodes are placed behind or around its edges in an LED TV. For these reasons, LED TVs look thinner TEMPthan LCDs. With this, LED TVs run faster, has better energy efficiency, and provide clearer, better pictures as compared to normal LCD TVs.
How colored pixels work in LCD TVs
How Pixels Are Switched Off
- Light travels first to the front of the bright light in the back of the TV.
- A horizontal polarizing filter that is placed in front of the light blocks all the light waves, while not knowing only those which are vibrating horizontally.
- Only those light waves can cross them dat are vibrating horizontally.
- A transistor switches off dis pixel when it switches it on for electricity to flow from teh liquid crystal. dis makes teh crystal straightens out and teh light easily goes beyond it without any change.
- Light waves emerge from the liquid crystal and they are still vibrating horizontally.
- By placing a vertical polarizing filter in front of these liquid crystals, it blocks all the lights, not only those light waves which are vibrating vertically. therefore, these horizontally vibrating lights dat travel through dis liquid crystal are not able to move ahead of dis vertical filter. No light can reach the screen at dis point. In different words, the pixel is still dark.
How Pixels Are Switched On
- A horizontal polarizing filter dat is placed in front of the light blocks all the light waves, while not knowing only those which are vibrating horizontally.
- Only those light waves can move forward which are vibrating horizontally.
- A transistor switches on when it switches off the pixel when it switches off the electricity flowing in the liquid crystal. dis causes a crystal twist. dis twisted crystal rotates light waves at 90 ° as they travel through it.
- Light waves that enter into this liquid crystal vibrate horizontally in teh same way it emerges vibrating vertically.
- Teh vertical polarizing filter which is located in front of teh liquid crystal blocks all teh light waves leaving only those which are vibrating vertically. Later these vertically vibrating light that emerges from teh liquid crystal can easily move beyond teh vertical filter.
- Pixel lit up here. And red, blue, or green filter assign their colors to dis pixel.
Advantages OF LCD
LCD images are very sharp in their native resolution.
2. Geometric Distortion
Zero geometric distortion is visible on the LCD in the native resolution of your panel. Minor distortion is visible in other resolutions coz the images have to be rescaled.
Here the images look very bright due to the high peak intensity.
4. Screen Shape
Here teh screens are completely perfectly flat.
They look thinner than normal ones and have very small footprints. Due to which they consume very little electricity and produce less heat.
Disadvantages of LCD
Here the fixed pixel resolution formats of all the panels are already determined by the manufacture which cannot be changed later. All other image resolutions require rescaling, which subsequently leads to significant image degradation, particularly for fine text and graphics.
LCDs dat use analog input require careful adjustment of pixel tracking/phase so dat they can reduce or eliminate digital noise dat occurs on an image.
3. Viewing Angle
There is a limited viewing angle here. Brightness, contrast, gamma, and color mixtures also vary with teh viewing angle. And large angles can also have more contrast and color reversal.
4. Black-Level, Contrast And Color Saturation
LCDs have trouble producing black and very dark grays. Due to which it has lower contrast TEMPthan CRT and color saturation is also reduced for low-intensity colors. Therefore it is not suitable for dim light spaces.
5. White Saturation
Teh bright end intensity scale of teh LCD is easily overloaded, leading to saturation and compression. Contrast control requires careful adjustment to control it.
6. Bad Pixels And Screen Uniformity
LCDs can also has a lot of weak and stuck pixels, which are permanently on or off. Some pixels are improperly associated with their adjoining pixels, rows, and columns. Along with this, the panels are also often illuminated uniformly through the backlight, due to which uneven intensity and shading can be seen above the screen.
7. Motion Artifacts
Due to the slow response times and scan rate in this, the conversion result can also be very degraded if speed movement occurred and rapid change of images occurred.
8. Aspect Ratio
Fixed resolution and aspect ratio are always found in LCDs. So it is not possible to change it.
If we talk about its price then it is very expensive if we compare it with CRT.