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An overview of LCD technology

Views: 324     Author: Reshine Display     Publish Time: 2023-09-28      Origin: Site


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An overview of LCD technology

Represents "Liquid Crystal Display." In TVs and computer monitors, LCD is a flat panel display technology that is widely used. Additionally, it is utilized in the screens of mobile gadgets like laptops, tablets, and smartphones.

In addition to looking different from clunky CRT (Cathode Ray Tube) monitors, LCDs also operate very differently. An LCD has a backlight that serves as a light source for each pixel arranged in a rectangular grid rather than shooting electrons at a glass screen. Red, Green, and Blue (RGB) sub-pixels are present in every pixel and can be turned on or off. It appears black when all of a pixel's sub-pixels are off. It appears white when all of the sub-pixels are fully illuminated. Millions of different color combinations can be created by varying the individual levels of red, green, and blue light. Click here for TFT LCD Display.

How are LCD screens made?

An LCD screen has two electrodes on glass substrates, two polarizers on each side, and a thin layer of liquid crystal material sandwiched between them. An optical filter known as a polarizer allows only certain polarizations of light to pass through while blocking all other polarizations. Since the electrodes must be transparent, ITO (Indium Tin Oxide) is the most widely used material.

Since LCD screens can't produce light on their own, a backlight is typically positioned behind them to make them visible in low light. The backlight's light sources can be either CCFLs or LEDs (Cold Cathode Fluorescent Lamps). The most widely used backlight is LED. Of course, an LCD cell can be made from a layer of a color filter if you prefer a color display. RGB color makes up the color filter. In front of an LCD, a touch panel can also be added.

LCD Display Structure

How do LCDs Operate?

Twisted Nematic, or TN, is the name of the first mass-produced LCD panel technology. The liquid crystal molecules in the LCD cell twist 90 degrees when an electrical field is not applied to them, which is how LCDs work. The light is polarized and twisted with the liquid crystal molecular layer when it passes through the first polarizer, whether it is ambient light or backlight. It is stopped when it gets to the second polarizer. The display is completely dark to the viewer.

The liquid crystal molecules are untwisted by an electric field when it is applied. When the polarized light reaches the layer of liquid crystal molecules, it does not undergo any twisting and instead passes through unaltered. The viewer will notice the display is bright when it passes through the second polarizer. LCD technology has a low power requirement because it uses electric fields rather than electric current (which electrons pass through).

How LCDs work

The Basics of LCD Displays

Passive matrix LCDs, the most basic LCDs described above, are typically used in low-end or straightforward applications like calculators, utility meters, early digital watches, alarm clocks, etc. Although passive matrix LCDs have many drawbacks, such as a small viewing angle, a slow response time, and poor brightness, they are excellent power consumers.

Scientists and engineers created active matrix LCD technology to address the shortcomings. TFT (Thin Film Transistor) LCD technology is the most popular. Even more cutting-edge LCD technologies are created based on TFT LCD. The IPS (In-Plane Switching) LCD is the most popular type. It features a very wide field of view, excellent picture quality, quick response, excellent contrast, fewer burn-in defects, etc.

IPS LCDs are frequently found in devices like LCD TVs, iPhones, pads, and LCD monitors. Samsung even reinvented LED backlighting with its QLED (quantum dot) technology, which turns off LEDs when no light is required to create deeper blacks.

Active TFT Color Display

Different LCD Types

1. The first is the TN (Twisted Nematic) display. Across all industries, LCD production is the most common and employs a variety of displays. Due to their low cost & quick response time compared to other displays, gamers use these displays the most frequently. The primary drawback of these displays is their poor quality, which also extends to their partial contrast ratios, viewing angles, and color reproduction. These tools, however, are adequate for daily tasks.

2. In-Plane Switching (IPS) Displays: Because they offer good image quality, greater viewing angles, vibrant color precision, and difference, IPS displays are regarded as the best LCDs. The majority of users of these displays are graphic designers, and in some other contexts, LCDs require the highest possible standards for image and color reproduction.

3. Vertical Alignment Panel: Between Twisted Nematic and in-plane switching panel technology, the vertical alignment (VA) panels can be placed anywhere in the middle. When compared to TN-type displays, these panels have higher quality features and the best viewing angles and color reproduction. The response time of these panels is quick. These, however, are much more practical and suitable for everyday use.

4. Compared to the twisted nematic display, this panel's structure produces deeper blacks and better colors. Better viewing angles can be achieved with some crystal alignments compared to TN-type displays. Because they are more expensive than other displays, these displays come with a cost. They also have low refresh rates & slow response times.

5. Advanced Fringe Field Switching (AFFS): When compared to IPS displays, AFFS LCDs offer the best performance and a wide range of color reproduction. The use of AFFS is very advanced because it can lessen color distortion without sacrificing a wide viewing angle. This display is typically used in highly sophisticated and formal settings, such as functional airplane cockpits.

6. Matrix displays can be either passive or active. The Passive-matrix type LCDs use a straightforward grid to allow charge to be delivered to a particular LCD pixel. A clear conductive material like indium-tin-oxide is used to create columns in one glass layer and rows in the other. Major flaws in the passive-matrix system include a slow responsea time that is slow and inaccurate voltage control. The ability of the display to update the currently displayed image is primarily indicated by the display's response time.

7. TFT (thin-film transistors) are the main component of LCDs of the active-matrix type. These are tiny switching transistors and capacitors that are arranged in a matrix on top of a glass substrate. Because every other row that the column intersects is turned OFF when the right row is activated, a charge can be transmitted down the precise column to address a particular pixel because the capacitor next to the targeted pixel receives a charge.

Advantages over other types of displays

Wall TVs, laptops, smartphones, and pads are all possible thanks to LCD technologies' great advantages of lightness, thinness, and low power consumption. It eliminated the opposition of numerous display technologies as it advanced. CRT monitors and plasma TVs are no longer commonplace in homes and offices. Presently, LCD Technologies rule the display industry. However, every technology has its limits.

LCD technologies require backlighting because of their slow response times, especially at low temperatures, and their constrained viewing angles. OLED (Organic Light Emitting Diodes) technology was created with a focus on the shortcomings of LCD. AMOLED (Active Matrix Organic Light Emitting Diodes) displays are now being used on a few high-end TVs and smartphones.

When compared to LCD technology, this cutting-edge technology offers even better color reproduction, crystal-clear image quality, a wider color gamut, and lower power usage. Please take note that PMOLED and AMOLED (Passive Matrix Organic Light Emitting Diodes) are types of OLED displays. Instead of PMOLED, you should choose AMOLED for your TV and mobile devices.

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