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Working and backlighting differences between LCD and LED

Views: 204     Author: Reshine Display     Publish Time: 2023-09-15      Origin: Site


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Working and backlighting differences between LCD and LED

What Exactly Is LCD?

LCD, which stands for "liquid crystal display," is a flat display technology that is commonly used in computer monitors, instrument panels, cellular phones, video cameras, televisions, laptops, tablets, and calculators. These display devices can produce high-resolution images. LCDs replaced the earlier cathode-ray tube (CRT) display technology; however, in recent years, other display technologies, such as light-emitting diodes (LEDs), have begun to replace LCDs. Click here for TFT LCD Display.

LCDs are commonly found on laptop computers and are available in both active-matrix and passive-matrix configurations. The LCD was invented in 1964 by RCA Laboratories in Princeton, New Jersey. The twisted-nematic (TN) method of operation was discovered in 1970, ushering LCD into mainstream applications. LCD manufacturers initially offered small screens for portable items such as watches and calculators.

Sharp Corporation introduced a 14-inch active-matrix full-color, full-motion screen in 1988, using a thin-film-transistor (TFT) array. As a result, Japanese manufacturers such as Hitachi established a legitimate — and eventually thriving — LCD business. Personal computers were the first to use large LCD screens, which were quickly followed by television receivers.

For their display grid, LCDs use an active or passive matrix. Thin-film transistor (TFT) displays are another name for active-matrix LCDs. A passive matrix LCD is made up of a matrix of conductors with pixels at each junction. To regulate the light for each pixel, a current is delivered through two conductors in the matrix.

A transistor is located at each pixel intersection in an active matrix, and it uses a lower current to adjust the brightness of a pixel. As a result, the power in an active-matrix screen can be switched on and off more frequently, increasing the refresh rate of the panel.

What Is LED?

An LED display is a flat-panel video display that uses light-emitting diodes as pixels. Because of their brilliance, these devices can even be used outside, where any visual output is visible even in direct sunlight — for store signage and billboards. Modern computer displays use a combination of LCDs and LEDs to illuminate the display regardless of ambient lighting conditions.

LED stands for light-emitting diode; when current flows through such diodes, light is produced. Electrons reunite with electron holes in the semiconductor material of an LED, emitting energy as photons. This is the fundamental principle of LEDs and LED displays.

LEDs have several advantages over incandescent light systems, including lower power consumption, longer lifespan, improved physical durability, smaller size, and faster switching. The LEDs in an LED display are very closely spaced. The diodes collectively produce a picture on display by adjusting the luminosity of each LED.

To create a vibrant color image, the concepts of additive color mixing are used, in which new colors are created by combining different light colors. An LED display is made up of red, green, and blue LEDs that are arranged in a specific pattern. These three colors combine to form a pixel. By varying the intensity of the diode, an LED device can produce billions of colors. The arrangement of colored pixels on an LED display appears as an image when viewed from a fixed distance.

Oleg Losev, a Russian inventor, invented the first LED in 1927. For many years, only infrared, red, and yellow LEDs could be used. These diodes were used in a variety of devices, ranging from remote controls to alarm clocks.

Shuji Nakamura, a Japanese physicist, invented a functional blue LED in 1994. Green and white LEDs appeared soon after, laying the groundwork for the explosion of LED applications in illumination and screen technologies.


To summarize, the terms light emitting diode (LED) and liquid crystal display (LCD) are used to describe different types of display technology. LED, rather than a fluorescent tube, employs backlighting technology. LED monitors last longer and produce sharper, higher-quality images than LCD monitors. The following are detailed explanations of the twelve key differences between LED and LCD:

1. Employment


A. As the name implies, liquid crystal display (LCD) panels use liquid crystals to toggle pixels on and off to expose a specific color.

B. Liquid crystals are analogous to a liquid-solid mixture in which an electric current can be used to change its form to trigger a specific response. These liquid crystals are analogous to window blinds.

C. When the window blinds are open, light enters the room freely. When the crystals in an LCD are positioned in a specific way, that light no longer passes through. The back of the LCD panel is in charge of transmitting light through the screen.

D. A display of red, green, or blue-colored (RGB) pixels is placed in front of the light. Liquid crystals are required to electrically activate or deactivate a filter in order to reveal or conceal a specific color in a pixel.

E. In contrast to CRT screens, which generate their light, LCD panels function by blocking light originating from the back of the screen. This allows LCD monitors and televisions to use significantly less energy than cathode ray tube (CRT) models. LCD televisions surpassed CRT televisions in global revenue for the first time in 2007.


A. LEDs are semiconductor devices that use quantum physics laws to convert electricity into light energy. Photons with energy are produced as electrons migrate from higher to lower states. This phenomenon is known as electroluminescence.

B. LED screens are made of a thin layer of highly distorted semiconductor material (i.e., with impurities inserted to regulate processes). LED semiconductors include gallium arsenide, gallium phosphide, gallium arsenide phosphide, and gallium indium nitride.

C. The diodes in an LED are oriented forward, allowing current to flow forward. This allows electrons in the conduction band of a semiconductor to recombine with holes in the valence band (or the most distant electron orbit within an atom).

D. As a result, whenever the recombination of holes and electrons produces a significant amount of energy in the form of heat and light, this energy is used to generate photons. The photons produce monochromatic or single-color light as a result.

E. Because of the thin semiconductor layer on the LED screen, photons can easily escape the junction and radiate outward, resulting in a vibrant, multicolored display.

2. Backlighting


A. LCDs display images on the screen by illuminating the crystal solution, which either blocks or allows light to pass through to create the images.

B. They require a light source because they do not produce light. Cold cathode fluorescent lamps (CCFLs) have traditionally provided a light source in LCDs, but they have been replaced by other sources such as LEDs or electroluminescent panels (ELPs).


A. Backlighting is a type of illumination that is used in LED and LCDs to illuminate the display on the screen. Without a backlight, display devices such as monitors or televisions would produce low-quality or dim images.

B. LED displays, unlike LCDs, generate their light. Light-emitting diodes are used as a light source to illuminate the crystal solution from behind to create images on the screen.

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