Lcd and led abbreviation: What’s the Difference Between LCD and LED?

Содержание

LED vs. LCD TVs Explained | What’s the Difference?

Thinking of putting together or upgrading your home theater setup? There are many factors to consider, but the process often begins with one major question: What kind of TV should you get? Current top-of-the-line TV technology like popular OLEDs from LG or QLED panels from Samsung might get a lot of attention, but they can still cost a pretty penny. Until overall OLED and QLED panels become more affordable, LED and LCD televisions still offer up a viable, quality option for the more budget-conscious.

But what’s the difference? It’s a question we hear often from home theater shoppers confused by all the jargon and acronyms. Here’s the quick answer: An LED TV is an LCD TV, but how the definition of each term became so muddled might come as a surprise.

See more

LED and LCD: Together forever

Despite having a different acronym, LED TV is just a specific type of LCD TV, which uses a liquid crystal display (LCD) panel to control where light is displayed on your screen. These panels are typically composed of two sheets of polarizing material with a liquid crystal solution between them. When an electric current passes through the liquid, it causes the crystals to align, so that light can (or can’t) pass through. Think of it as a shutter, either allowing light to pass through or blocking it out.

Since both LED and LCD TVs are based around LCD technology, the question remains: what is the difference? Actually, it’s about what the difference was. Older LCD TVs used cold cathode fluorescent lamps (CCFLs) to provide lighting, whereas LED LCD TVs used an array of smaller, more efficient light-emitting diodes (LEDs) to illuminate the screen.

Since the technology is better, all LCD TVs now use LED lights and are colloquially considered LED TVs. For those interested, we’ll go deeper into backlighting below, or you can move onto the Local Dimming section.

Backlighting

Three basic illumination forms have been used in LCD TVs: CCFL backlighting, full-array LED backlighting, and LED edge lighting. Each of these illumination technologies is different from one another in important ways. Let’s dig into each.

CCFL Backlighting

CCFL backlighting is an older, now-abandoned form of display technology in which a series of cold cathode lamps sit across the inside of the TV behind the LCD. The lights illuminate the crystals fairly evenly, which means all regions of the picture will have similar brightness levels. This affects some aspects of picture quality, which we discuss in more detail below. Since CCFLs are larger than LED arrays, CCFL-based LCD TVs are thicker than LED-backlit LCD TVs.

Full-array backlighting

Full-array backlighting swaps the outdated CCFLs for an array of LEDs spanning the back of the screen, comprising zones of LEDs that can be lit or dimmed in a process called local dimming. TVs using full-array LED backlighting to make up a healthy chunk of the high-end LED TV market, and with good reason — with more precise and even illumination, they can create better picture quality than CCFL LCD TVs were ever able to achieve, with better energy efficiency to boot.

Edge lighting

Another form of LCD screen illumination is LED edge lighting. As the name implies, edge-lit TVs have LEDs along the edges of a screen. There are a few different configurations, including LEDs along just the bottom, LEDs on the top and bottom, LEDs left and right, and LEDs along all four edges. These different configurations result in picture quality differences, but the overall brightness capabilities still exceed what CCFL LCD TVs could achieve. While there are some drawbacks to edge lighting compared to full-array or direct backlight displays, the upshot is edge lighting that allows manufacturers to make thinner TVs that cost less to manufacture.

To better close the local-dimming quality gap between edge-lit TVs and full-array back-lit TVs, manufacturers like Sony and Samsung developed their own advanced edge lighting forms. Sony’s technology is known as “Slim Backlight Master Drive,” while Samsung has “Infinite Array” employed in its line of QLED TVs. These keep the slim form factor achievable through edge-lit design and local dimming quality more on par with full-array backlighting.

What is local dimming?

Local dimming is a feature of LED LCD TVs wherein the LED light source behind the LCD is dimmed and illuminated to match what the picture demands. LCDs can’t completely prevent light from passing through, even during dark scenes, so dimming the light source itself aids in creating deeper blacks and more impressive contrast in the picture. This is accomplished by selectively dimming the LEDs when that particular part of the picture — or region — is intended to be dark.

Local dimming helps LED/LCD TVs more closely match the quality of modern OLED displays, which feature better contrast levels by their nature — something CCFL LCD TVs couldn’t do. The quality of local dimming varies depending on which type of backlighting your LCD uses, how many individual zones of backlighting are employed, and the quality of the processing. Here’s an overview of how effective local dimming is on each type of LCD TV.

Full-array and direct local backlighting

TVs with full-array backlighting have the most accurate local dimming and therefore tend to offer the best contrast. Since an array of LEDs spans the entire back of the LCD screen, regions can generally be dimmed with more finesse than on edge-lit TVs, and brightness tends to be uniform across the entire screen. Vizio’s impressive P-Series are great examples of relatively affordable models that use multiple-zone, full-array backlighting with local dimming.

“Direct local dimming” is essentially the same thing as full-array dimming, just with fewer LEDs spread further apart in the array. However, it’s worth noting that many manufacturers do not differentiate “direct local dimming” from full-array dimming as two separate forms of local dimming. We still feel it’s important to note the difference, as fewer, further-spaced LEDs will not have the same accuracy and consistency as full-array displays.

Edge lighting

Because edge lighting employs LEDs positioned on the edge or edges of the screen to project light across the back of the LCD screen, as opposed to coming from directly behind it, it can result in very subtle blocks or bands of lighter pixels within or around areas that should be dark. The local dimming of edge-lit TVs can sometimes result in some murkiness in dark areas compared with full-array LED TVs. It should also be noted that not all LED edge-lit TVs offer local dimming, which is why it is not uncommon to see glowing strips of light at the edges of a TV and less brightness toward the center of the screen.

CCFL Backlighting

Since CCFL backlit TVs do not use LEDs, models with this lighting style do not have dimming abilities. Instead, the LCD panel of CCFL LCDs is constantly and evenly illuminated, making a noticeable difference in picture quality compared to LED LCDs. This is especially noticeable in scenes with high contrast, as the dark portions of the picture may appear too bright or washed out. When watching in a well-lit room, it’s easier to ignore or miss the difference, but in a dark room, it will be, well, glaring.

OLED vs. QLED

As if it wasn’t already confusing enough, once you begin exploring the world of modern display technology, new acronyms crop up. The two you’ll most commonly find are OLED and QLED.

Despite the similar-sounding name, OLED (organic light-emitting diode) TVs are in a category all their own. We have an in-depth guide on the differences between OLED and QLED displays, but here’s a quick overview.

An OLED display uses a panel of pixel-sized organic compounds that respond to electricity. Since each tiny pixel (millions of which are present in modern displays) can be turned on or off individually, OLED displays are called “emissive” displays (meaning they require no backlight). They offer incredibly deep contrast ratios and better per-pixel accuracy than any other display type on the market.

Because they don’t require a separate light source, OLED displays are also amazingly thin — often just a few millimeters. OLED panels are often found on high-end TVs in place of LED/LCD technology, but that doesn’t mean that LED/LCDs aren’t without their own premium technology.

QLED is a premium tier of LED/LCD TVs from Samsung. Unlike OLED displays, QLED is not a so-called emissive display technology (lights still illuminate QLED pixels from behind). However, QLED TVs feature an updated illumination technology over regular LED LCDs in the form of Quantum Dot material (hence the “Q” in QLED), which raises overall efficiency and brightness. This translates to better, brighter grayscale and color and enhances HDR (High Dynamic Range) abilities.

The situation is likely to get even more confusing in the near future; Samsung is developing tech that combines QLED and OLED to give users the best from both. 

For a further description of QLED and its features, read our list of the best TVs you can buy. The article further compares the qualities of both QLED and OLED TV; however, we also recommend checking out our OLED vs. QLED piece for a side-by-side look at these two top-notch technologies. 

There are more even displays to become familiar with, too, including microLED and Mini-LED, which are lining up to be the latest head-to-head TV technologies. Consider checking out how the two features compare to current tech leaders in the OLED vs. MicroLED guide and our Mini-LED vs. QLED guide.

In the world of TV technology, there’s never a dull moment. However, with this detailed research, we hope you feel empowered to make an informed shopping decision and keep your Best Buy salesperson on his or her toes.

Editors’ Recommendations

abbreviation and shortcuts-of-led-lce-tv-terms for beginner

Hi friends welcome to my website

Abstract:

In our day-to-day life, we are using often shortcut words but some words only we know the abbreviation especially the electronics shortcuts mostly we don’t know. and we are not trying to know also. so in this page, I will give the ABBREVIATIONS AND SHORTCUTS LED/TV

General 

LED TV – LIGHT-EMITTING DIODE TV

LCD TV – LIQUID CRYSTAL DISPLAY TV

OLED – ORGANIC LIGHT-EMITTING DIODE

QLED – QUANTUM -DOT LIGHT-EMITTING DIODE

ULED – ULTRA LIGHT-EMITTING DIODE

HDTV – HIGH DEFINITION TELEVISION

FHDTV – FULL HIGH DEFINITION TELEVISION

UHD – ULTRA HIGH DEFINITION TELEVISION

CCFL – COLD CATHODE FLUORESCENT LAMP

CFL – COMPACT FLUORESCENT LAMP

(ABBREVIATIONS AND SHORTCUTS LED/TV)

Processor 

ADC – ANALOG TO DIGITAL CONVERSION

MPU– MICRO PROCESSOR UNIT

MCU – MICROCONTROLLER UNIT

DSP — DIGITAL SIGNAL PROCESSOR

SOC – SYSTEM ON CHIP

RAM – RANDOM ACCESS MEMORY

DRAM – DYNAMIC RANDOM ACCESS MEMORY

ROM – READ-ONLY MEMORY

EPROM – ERASABLE PROGRAMMABLE READ-ONLY MEMORY

EEPROM – ELECTRICALLY  ERASABLE  PROGRAMMABLE  ROM

DDR – DOUBLE DATA RATE

SD – SECURE DIGITAL

Power supply 

PWM – PULSE WIDTH MODULATION

PSU — POWER SUPPLY UNIT

SMPS — SWITCHED-MODE POWER SUPPLY

PFC – POWER FACTOR CORRECTION

OVP – OVERVOLTAGE PROTECTION

STB – STANDBY

STBV – STANDBY VOLTAGE

Signals And Voltage 

LVDS – LOW VOLTAGE DIFFERENTIAL SIGNAL

T-CON  — TIMING CONTROL  BOARD

LDO – LOW DROP OUT (REGULATOR )

DC to DC – DIRECT CURRENT to DIRECT CURRENT

AVDD – ANALOG DRAIN VOLTAGE

DVDD – DIGITAL DRAIN VOLTAGE

VREF – REFERENCE VOLTAGE

VCOM – COMMON VOLTAGE ( or ) SHARED VOLTAGE

VGH – HIGH VOLTAGE (+Ve)

VGL – LOW VOLTAGE (-Ve)

VON – VOLTAGE ON

VOFF – VOLTAGE OFF

CVP – CONTINUED VERIFICATION PROCESS

CPV – CLOCK PULSE VERTICAL

VA – VERTICAL ALIGNMENT

HA – HORIZONTAL ALIGNMENT

CE  – CHIP ENABLE

OE – OUTPUT ENABLE

CS – CHIP SELECT

STV – START VERTICAL

CKV — CLOCK VOLTAGE

CLK – CLOCK

 FOR VIDEO CLICK HERE 

ABBREVIATIONS AND SHORTCUTS LED/TV

OSD – ON-SCREEN DISPLAY

SMD – SURFACE MOUNT DEVICE

ESD  – ELECTROSTATIC DISCHARGE ( LED PROTECTION )

COF  – CHIP ON FLIM

ACF  – ANISOTROPIC CONDUCTIVE FLIM

FPC  – FLEXIBLE PRINTED CIRCUIT

FFC  – FLAT FLEXIBLE CABLE

FPD  – FLAT PANEL DISPLAY

TAB  – TAPE AUTOMATED BONDING

TCP  – TAPE CARRIER PACKAGE

TFT  – THIN FILM TRANSISTOR

IPS LCD  – IN-PLANE SWITCHING LCD

VGA  – VIDEO GRAPHICS ARRAY

RGB  – RED, GREEN, BLUE

HDMI – HIGH DEFINITION MULTIMEDIA INTERFACE

IR   – INFRARED

90,000 What are OLED displays and is it really a breakthrough in the screen market

How OLEDs are saving energy and which technology will dominate in the coming years

From this article you will learn:

How OLED Displays Work

OLEDs are organic light-emitting diodes (OLEDs) that independently emit light when an electric current passes through them.In English, this abbreviation stands for Organic Light Emitting Diod.

If translated into Russian, you get organic light-emitting displays. Organic doesn’t mean living. Here, organic matter refers to carbon-containing polymers that phosphoresce when a current is passed through them. Moreover, they shine the brighter, the more current is applied to them. If no current is applied at all, there will be no glow.

OLED technology has outperformed LCD and LED in many ways.Until recently, OLED matrices were found only in smartphones and TVs. In 2020, ASUS began the release of laptops with OLED displays.

Photo: ASUS

How OLED differs from LED and LCD

  • A key difference between OLED screens and the more common liquid crystal options is that LCDs or LEDs require an external backlight .Such displays are composed of many layers, resulting in an increase in the thickness of the devices.

Actually, these layers are also needed to accommodate the backlight: to minimize the volume, it is customary to place it on the sides. In simpler versions, the entire LCD screen glows: in fact, the screen turns into one large lamp that shines directly into the user’s eyes.

OLED screens do not need such a backlight: as soon as a current is applied to the device, the necessary diodes start to glow without additional stimulation.”Necessary” is a defining word when describing OLED technology.

Since it is not specific pixels that light in LCD and LEDs, but the backlight under the pixel groups, even a crystal black screen will be a little overexposed – “grayish”. In OLED, only those pixels (diodes) that should light up. As a result, the contrast ratio of OLED displays can be as high as a million to one, while LED options offer a thousand to one.

  • Weight of the device. If LED displays need to fit all the “stuffing” inside, then OLED has fewer layers.Therefore, they turn out to be lighter and thinner. This setting is especially important for large wall-mounted TVs and laptops: lighter laptops are easier to carry around. And lightweight wall-mounted TV screens are easier to mount on the wall.
  • Power consumption. LCD and LED screens always consume electricity, since the backlight is needed every second of operation. OLED consumes fewer watts.
  • Possibility to bend the screen. Forming an OLED display from thousands of small diodes allows you to give it any shape: for example, a semicircle in the case of large TVs.Smartphone manufacturers place an OLED screen on the edges of phones – it turns out that the display seems to “fit” on the side edges of the phone.
  • There is another property that distinguishes OLEDs from previous generation LCD screens: the is the speed of diode response. True, you can only notice the absence of lags on OLED displays when watching sports broadcasts or fighting scenes in action films, where the picture changes very quickly.

Most modern gadgets, be they TVs, laptops or smartphones, are equipped with LED screens.But OLED has already won in the premium segment: such displays are put on the most advanced models.

Color rendering of LCD and OLED screens

(Photo: ASUS)

“The development process for display technology is slow in itself.As practice shows, it takes 30-40 years from the moment of creation to mass use, – said Vlad Zakharov, ASUS Marketing Director in Russia, CIS and Baltic countries. “The massive proliferation of OLED technology is happening at the moment: in the next few years, everyone will only talk about OLED.”

Why OLED shows clearer than plasma

In the mid-2000s, there was already an alternative to standard LCD displays – plasma screens. A decade ago, they produced sharper images than LCDs and were considered a breakthrough technology.In 2014, the story reached a dead end: manufacturers considered the development of plasma screens unprofitable and stopped producing all such devices.

Plasma TVs can now be purchased hand-held, as some still feel that they still offer better picture quality. In fact, liquid crystal displays have come a long way, and even modern LCDs have surpassed plasma displays.

Difference in picture quality between LCD and OLED displays

(Photo: ASUS)

It’s all about the pixel size.The smaller it is, the higher resolution an arbitrarily small screen can get. Plasma display technology implies a certain pixel size, which cannot be reduced if desired. This is invisible on giant wall-to-wall screens, but becomes critical when choosing a compact TV or laptop.

The reason is that each pixel in plasma screens is a cross-section of a tube into which an inert gas is injected. This gas is in the fourth state of aggregation – plasma, which is where the name comes from.These tubes should be placed compactly under the display surface. It turns out that in small sizes, plasma screens cannot produce as clear an image as OLEDs and even LCDs of the 2020s – the “plasma” has a larger pixel.

OLED vs IPS: which to choose

IPS is not an alternative technology, but a type of LCD matrix. Basically, all IPS displays are the same LED screens that scatter incoming light, while OLED screens emit light.

Color rendering of LCD and OLED displays at the same brightness level

(Photo: ASUS)

Benefits of OLED versus IPS:

  • OLED screens are generally thinner and lighter than IPS;
  • OLED contrast can be several orders of magnitude higher than IPS;
  • OLED uses less electricity than IPS devices;
  • All IPS screens are strictly flat.OLED can be made both flat and curved;
  • The 90,023 pixels in OLED are closer to the screen, so the image is distorted less at an angle than on IPS displays.

Disadvantages of OLED versus IPS

  • Service life. Each pixel has a certain duration of operation, and if each one shines on its own, then sooner or later burnout will come. Of course, IPS is also not forever, but with a comparable intensity of use, IPS should last longer.

Some manufacturers have figured out how to get around this limitation. “For OLED displays, it is not recommended to use a static image of elements for an extended period of time – this will help to avoid the problem of fading,” says Vlad Zakharov. – For our part, all OLED laptops will be preinstalled with a black screensaver with animation in the form of soap bubbles. This will protect the screen when the laptop is not in use. ”

  • Effects on vision. People with high pupil sensitivity may notice OLED flicker. This flickering is caused by a higher frame rate: pixels fade and light up more often, and it becomes difficult for the eyes to perceive it. Not every OLED owner experiences eye fatigue, but it’s worth keeping this in mind when choosing between IPS and OLED.

Photo: ASUS

OLED vs AMOLED: What’s the Difference

AMOLED is the top-end variety of OLED displays.If OLED is a whole class, then AMOLED is a subspecies ideal for touchscreens. The peculiarity of AMOLED is that an additional layer is added to the standard layers of an OLED display: an active matrix made of thin-film transistors – almost the same as in IPS-displays. This means that AMOLED combines the advantages of IPS and classic OLED.

The transistor layer allows you to “remember” information that is necessary to maintain pixel compatibility. As a result, the clarity of the image is improved.A side effect is the thickening of the screen, as well as the risk of depressurization: if the AMOLED transistor layer “peels off” from the main OLED display, the screen will quickly lose all its color reproduction capabilities.

AMOLED “at maximum speed” is SuperAMOLED. Here, the active matrix of silicon transistors is connected to the rest of the display layers, and depressurization is not terrible. Therefore, if there is a choice between OLED and AMOLED, then the second option will give a gain in image quality, but the first will avoid the risk of sudden fading.If you need to choose between OLED and SuperAMOLED, then the latter option is preferable.

OLED vs QLED: Pros and Cons of

QLEDs are displays based on quantum dots, that is, on ultra-small charge carriers a few nanometers in size. QLED is considered to be the next step in the evolution of displays due to an even more noticeable reduction in pixel size, and with it, increased image clarity.

At the same time, in the currently existing displays, which are positioned as QLED, quantum dots are used exclusively for backlighting.They don’t generate the image on their own. This means that commercially available QLED devices are simply high-quality images without a genuine breakthrough in technology. A good alternative for OLED, but nothing more.

There is still no complete QLED TV or QLED laptop. Research in the field of quantum dots has been going on since the 1990s, but no one has yet released a ready-to-sell product with such a display.

Giant companies are investing billions of dollars in this area and are announcing the appearance of true QLED screens by the mid-2020s.In 2011, Samsung showed a prototype of a four-inch QLED display. Whether engineers will be able to bring this technology to mind is not yet clear.

Trends in the display market in the coming years

  • Replacing LED displays with more modern OLED displays. Only the price stops the mass update: as of 2021, OLEDs are more expensive. But the rapid development of this technology and the opening of new plants will inevitably lead to a reduction in cost – the only question is the timing.
  • Capturing the upper price bracket with even more advanced screens like TOLED. These are transparent screens that make it easy to see the image even in very bright light.
  • Augmented reality. The absolute transparency of TOLED displays will allow you to mount them directly on the windows or windshields of cars and, if necessary, display pop-up tips for the driver when driving on the road. The technology can also be adapted for helmets: a great find for motorcyclists, pilots and professional racers.
  • microLED technology. “This technology should address a major flaw in current OLED panels: OLED burnout. In microLED technology, OLED has been replaced by a microscopic gallium nitride LED that can last much longer and is not subject to fading. For the next ten years, the microLED developers have a major challenge – to achieve a qualitatively new approach to soldering microscopic LEDs, so that it becomes possible to increase the number of pixels per inch.Accordingly, in terms of the quality of the display structure, microLED will be able to catch up with OLED. Over time, the cost of microLED production will decrease so much that the technology will compete with OLED panels, ”said Vlad Zakharov.
  • Another promising development is PHOLED. It uses ultra-high efficiency electrophosphorescence diodes. While the classic OLED converts only 25% of the received electricity into light, then the efficiency of PHOLED tends to 100%. Consequently, energy is spent four times less, and huge savings are formed: both in money and in the size of the battery for a smartphone or laptop.

But more importantly, the efficiency of PHOLED will make possible the long-held dream of science fiction writers: turning entire walls into a display. The low power consumption of such diodes will allow them to cover, for example, the wall of a room and illuminate the room with diodes, not a light bulb. This will change the way houses are lit and make buildings with luminous walls a familiar attribute of the cityscape.

90,000 LCD TV – synopsis LCD TV


This file is associated with 1 file (s).Among them: Document Microsoft Word.docx.
Show all related files


A selection in the database: Emergency work.doc, Laboratory work on programming on VBA.docx, 3.Analysis of educational work for the last year.doc, Examination of the topic, literature I course.doc, Purpose, types, device and the use of manual firefighters forest, Speech to defend Coursework..doc, purpose of the work.docx, Title Principle Ayaulym 21 mamyr.docx, 10 principles of my life.pdf, Tests for the work of OKS, PHC, 2016.doc


LCD TV

Modern TVs use digital signal processing. For example, COFDM is a coded orthogonal frequency division data processing commonly used in television. The abbreviation LVDS is a method of transmitting signals to a matrix. Inverter – generates voltage for backlight lamps (or LEDs in LCD and OLED TVs) and regulates it. Flash memory (ROM) is the TV’s own memory that stores information about your settings, built-in functions, and receiver management.RAM – random access memory, participates in data processing during operation

Block diagram of an LCD TV

In the schematic diagram, positional designations of elements of capacitors, resistors and so on are used to divide into functional blocks. For example, R805, C806 will refer to the power supply, and R705 and C706 will refer to line scan. The corresponding designations will also be present on the TV chassis board.

Design and principle of operation of LCD TV

LCD (Liquid crystal display) or LCD (liquid crystal) TV, as they are popularly called, is a TV with LCD display and lamp backlight.Liquid crystal means that the display (monitor) itself is made on the basis of liquid crystals

A little history:

Liquid crystals were first discovered by the Austrian botanist Reinitzer in 1888, but only in 1930 researchers from the British corporation Marconi received a patent for their industrial application, however, the weakness of the technological base did not allow at that time to actively develop this direction.

The first real breakthrough was made by scientists Fergeson and Williams from the American corporation RCA.One of them created a thermal sensor based on liquid crystals, using their selective reflective effect, the other studied the effect of an electric field on nematic crystals.

In the second half of the 70s, the transition from eight-segment LCD displays to the production of matrices with addressing (controllable) of each point began.

Now LCD displays have almost completely ousted CRT TVs from the market, offering the buyer any size. The price range is also very large and allows everyone to choose a TV set according to their needs and financial capabilities.

The circuitry of LCD TVs is much more complicated than that of simple CRT TVs: miniature parts, multilayer boards, expensive blocks …

Circuitry of an LCD TV.

Design and principle of operation:

The LCD display is based on the phenomenon of luminous flux polarization. It is known that the so-called polaroid crystals are capable of transmitting only that component of light, the electromagnetic induction vector of which lies in a plane parallel to the optical plane of the polaroid.For the rest of the luminous flux, the polaroid will be opaque. This effect is called light polarization.

Structurally, the display consists of an LCD matrix (a glass plate, between the layers of which liquid crystals are located), light sources for backlighting, a contact harness and a frame (case), usually plastic, with a metal frame of rigidity.

Each pixel of an LCD matrix consists of a layer of molecules between two transparent electrodes, and two polarizing filters, the polarization planes of which are (as a rule) perpendicular.In the absence of liquid crystals, the light transmitted by the first filter is almost completely blocked by the second.

The surface of the electrodes in contact with liquid crystals is specially treated for the initial orientation of molecules in one direction. In a TN matrix, these directions are mutually perpendicular; therefore, in the absence of stress, the molecules are arranged in a helical structure.

Cold cathode fluorescent lamps are used as the light source (LCD backlight) (so called because the cathode that emits electrons (negative electrode) inside the lamp does not need to be heated above ambient temperature to light the lamp).This is how a lamp for an LCD TV may look like, on the right photo is a “lamp assembly in operation” for a TV with a large diagonal LCD display:

The lamps themselves (bright white glow) are located in special case clamps, behind them is a reflector, to reduce loss of luminous flux. In order for the LCD matrix to light up evenly (and not striped, like the lamps are installed, there is a diffuser in front of the screen, which evenly distributes the light flux over its entire area.Unfortunately, in this place there is also a considerable loss of the “brightness” of the lamps.

Modern LCD matrices have a fairly good viewing angle (about 160 degrees) without loss of image quality (colors, brightness). The most unpleasant thing that you can see on them is these “broken pixels”, however, given that their size is very small, one or two such “burned-out” pixels will not greatly interfere with watching movies and broadcasts, but on the monitor screen – this can already be quite unpleasant

Dead pixels

Advantages and disadvantages:

Compared to CRT TVs, LCD panels have excellent focusing and clarity, there are no beam alignment errors or violation of the image geometry, the screen never flickers, they are lighter and take up less space.The disadvantages include weak (compared to CRT) brightness and contrast, the matrix is ​​not as strong as the CRT screen, a set of digital brakes and glitches with an analog or weak signal, as well as poor processing of the source material …

LED TV

Although LED is similar in spelling to OLED, it means a completely different technology. Liquid crystal LED TV, what it means is an LCD device using LED backlighting.

And if OLED (Organic Light-Emitting Diode) means that the screen consists of organic light-emitting diodes, then LED (Light Emitting Diode) is the use of diodes to illuminate the matrix of an LCD TV receiver.

LED (Light Emitting Diode) is a light emitting diode, and in television technology this abbreviation means a screen on a liquid crystal matrix (LCD) and backlit from these light emitting diodes.

Whereas conventional LCD TVs use a cold cathode lamp, the same Cold Cathode Fluorescent Lamps (CCFL), LCD LEDs use light emitting diodes. As you know, LCD (LCD) screens in TVs consist of cells (pixels) with liquid crystals and, depending on the position of the crystal in the cell, transmits light or not. This creates a glow on the screen.

The quality of the LCD matrix determines such parameters as static contrast, black level, viewing angles, refresh rate, response time.There are such technologies for the production of liquid crystal matrices for TVs: TN, IPS (S-IPS, IPS-Pro, P-IPS, AH-IPS), VA / MVA / PVA, PLS.

The backlight affects such parameters as brightness, color rendering, color gamut, dynamic contrast. Although it is more correct to consider the matrix + backlight system in the TV and measure the parameters for it.

Manufacturers claim that the use of LED backlighting can increase:

• brightness,

• contrast,

• image clarity,

• color gamut.

The power consumption of the LED TV is also reduced by about 40%. Also, ice TVs do not use mercury, which is used in fluorescent lamps, which affects the environment.

White or composite LEDs

Technologically, the display backlight in an LCD TV is carried out from LEDs. For this, white diodes are used, the light from which hits the light filters and get blue, green and red colors. This type is called WLED.

To improve the color gamut, at first, three types of LEDs were used as backlighting: red, green, blue.This technology is called RGB LED.

Currently, premium TVs use composite diodes (GB-R LED, RB-G LED) or quantum dots.

In composite LEDs, blue and green are combined into one and covered with a red phosphor (GB-R), or in another case, red and blue are combined and covered with a green phosphor (RB-G).

Quantum Dots in LED TV

Quantum Dot Enhancement Film (QDEF) and uses “quantum dots” in its work.It uses a blue LED, and uses quantum dots as a light filter to produce green and red.

Quantum dots in the TV replace some of the diodes, in this case red and green. All that remains is the blue LED, which forms a stream of light both to excite the quantum dots and to operate the blue sub-pixels on the screen. And the flow of light onto the red and green sub-pixels forms quantum dots.

Methods of LED backlighting

To improve the image quality on the TV screen, local dimming technology has appeared, according to which LEDs are controlled by groups of several diodes.The local dimming system has several drawbacks:

1. Poor color uniformity in the image, that is, bright and dark spots are noticeable in areas where the backlight is brightly on and off.

2. Color halos appear on contrasting transitions.

3. Image detail disappears in dark areas.

These shortcomings are difficult to determine from the usual video picture on the TV screen, therefore today the local dimming method is widely used in models with LED backlighting.

You can also divide LED TVs according to the way the LEDs are arranged: Direct and Edge.

Direct – this is when the diodes are evenly located behind the screen, in the form of a matrix.

Edge – this is when they are located along the perimeter of the screen together with the diffusing panel. With this arrangement, effective local dimming cannot be done.

With the Direct method, you can get more uniform backlighting compared to the Edge method, but the TV thickness and power consumption will increase by increasing the number of LEDs.Ultra-thin TVs (thickness can be less than 3 centimeters) can only be obtained using the edge diode arrangement.

Because of its economy and at the same time showing fairly good results, the most commonly used edge (Edge) backlight with local dimming.

LED TV, what does it mean

Although the writing of LED is similar to OLED, it denotes a completely different screen construction technology. What does a liquid crystal LED TV mean is a TV with an LCD matrix and backlit LEDs.

And if OLED (Organic Light-Emitting Diode) means that the screen consists of organic light-emitting diodes, then LED (Light Emitting Diode) is the use of diodes to illuminate the matrix of an LCD TV receiver.

LED (Light Emitting Diode) is a light emitting diode, and in television technology, this abbreviation means a screen on a liquid crystal matrix (LCD) and backlit from these light emitting diodes. After the introduction of a new type of backlighting, TV manufacturers began to replace “LCD” with “LED” in model names.

This was done more from a marketing point of view. In fact, this was not a new screen technology, but just a different kind of backlighting. But this name of televisions has survived and is used today.

As you know, lcd (lcd) screens in televisions consist of cells (pixels) with liquid crystals and, depending on the position of the crystal in the cell, transmits light or not. This creates a glow on the screen.

The quality of the LCD matrix depends on such parameters as static contrast, black level, viewing angles, refresh rate, response time.There are such technologies for the production of liquid crystal matrices for TVs: TN, IPS (S-IPS, IPS-Pro, P-IPS, AH-IPS), VA / MVA / PVA, PLS.

Today TN matrices have left the market due to their low quality in terms of color rendition, they are used for pc monitors.

IPS and VA matrices with their own varieties were developed. There is also a new ADS matrix.

The backlight affects such parameters as brightness, color rendition, color gamut, dynamic contrast.Although it is more correct to consider the matrix + backlight system in the TV and measure the parameters for it.

Manufacturers claim that the use of LED backlighting can increase:

  • brightness,
  • image clarity,
  • 90,023 colors.

The power consumption of the LED TV is also reduced by about 40%. Also, ice TVs do not use mercury, which is used in fluorescent lamps, which affects the environment.

Indeed, modern ultra-bright LEDs can provide high brightness of the image on the display.

The contrast is increased and the concept of dynamic contrast is introduced, when the brightness of the LEDs is adjusted locally for different parts of the screen, and due to this, the dynamic contrast ratio increases. At the same time, the level of static contrast of the TV remains the same, it depends on the display matrix.

The black level is also improved by adjusting the light of the diodes while watching the video.In a dark scene, the backlight level decreases and the screen gets darker, and hence the black level improves.

But about increasing the color gamut of the TV, here you need to consider everything in more detail.

Gamut and color gamut information.

White or composite LEDs

Technologically, the display backlight in LCD TV is carried out from LEDs. For this, white diodes are used, the light from which hits the light filters and get blue, green and red colors.This type is called WLED.

To improve the color gamut, at first, three types of LEDs were used as backlighting: red, green, blue. This technology is called RGB LED.

But it was not possible to obtain the required spectrum of light with the help of such technologies. And the color gamut was insufficient for use on UHD TVs. To solve this problem, new types of LEDs in televisions have been invented.

Currently, premium TVs use composite diodes (GB-R LED, RB-G LED) or quantum dots.

In composite LEDs, blue and green are combined into one and covered with a red phosphor (GB-R), or in another case, red and blue are combined and covered with a green phosphor (RB-G).

Details of the differences in WLED, RGB and GB-R LED backlighting.

Quantum dots in LED TV

A completely different technology for changing the WLED backlight was proposed by Nanosys.

This technology is called Quantum Dot Enhancement Film (QDEF) and uses “quantum dots” in its work.It uses a blue LED, and uses quantum dots as a light filter to produce green and red.

Quantum dots in the TV replace some of the diodes, in this case red and green. All that remains is the blue LED, which forms a stream of light both to excite the quantum dots and to operate the blue sub-pixels on the screen. And the flow of light onto the red and green sub-pixels forms quantum dots.

Learn more about quantum dots.

Ice Backlight Methods

To improve the quality of the image on the TV screen, the local dimming technology appeared, according to which the LEDs are controlled by groups of several diodes.The local dimming system has several disadvantages:

  1. Poor color uniformity in the image, that is, bright and dark spots are noticeable in areas where the backlight is brightly on and off.
  2. Colored halos appear on contrasting transitions.
  3. Dark areas are missing image details.

These shortcomings are difficult to determine from the usual video picture on the TV screen, so today the local dimming method is widely used in models with led backlighting.

You can also divide LED TVs according to the way the LEDs are arranged: Direct and Edge.

Direct – this is when the diodes are evenly located behind the screen, in the form of a matrix.

Edge is when they are located along the perimeter of the screen together with the diffusion panel. With this arrangement, effective local dimming cannot be done.

With the Direct method, you can get more uniform backlighting than the Edge method, but the TV thickness and power consumption will increase by increasing the number of LEDs.Ultra-thin TVs (thickness can be less than 3 centimeters) can only be obtained using the edge diode arrangement.

Because of its economy and at the same time showing fairly good results, the most commonly used edge (Edge) backlight with local dimming.

What is a liquid crystal display (LCD)?

The

Abbreviation Liquid Crystal Display (LCD) is a flat, thin display that replaces the old CRT display.The LCD provides better image quality and high resolution support.

Generally, LCD refers to a type of monitor that uses LCD technology, as well as flat panel displays such as laptops, calculators, digital cameras, digital clocks, and other similar devices.

Photo from Amazon

There is also an FTP command that uses the letters “LCD”. If that’s what you want, you can read more about it on Microsoft’s website, but this has nothing to do with computers or TVs.

How do LCD screens work?

Like shows liquid crystal display , LCD screens use liquid crystals to turn pixels on and off to show a specific color. Liquid crystals are like a mixture between a solid and a liquid, where an electric current can be applied to change their state so that a specific reaction occurs.

These liquid crystals can be thought of as window shutters. When the shutter is open, light can easily enter the room.On LCD screens, when the crystals are aligned in a special way, they no longer allow this light to pass through.

This is the back of the LCD screen that is responsible for light through the screen. In front of the light is a screen made up of red, blue or green pixels. Liquid crystals are responsible for electronically turning the filter on or off to reveal a specific color or keep that pixel black.

This means that LCD screens work by blocking light from the back of the screen instead of creating the light itself, like CRT screens work.This allows LCD monitors and TVs to consume much less power than CRT monitors.

LCD vs LED: What’s the Difference?

LED stands for LED. Although it has a different name than the liquid crystal display, it is not something completely different, but just another type LCD screen.

The main difference between LCD and LED screens is how they provide backlighting. Backlight refers to how the screen turns the light on or off, which is critical to delivering great images, especially between the black and colored areas of the screen.

Conventional LCD screens use a cold cathode fluorescent lamp (CCFL) for backlighting, while LED screens use more efficient and smaller LEDs (light emitting diodes). The difference between the two is that CCFL backlit LCDs may not always block all blacks, in which case something like a black and white scene in a movie may not look as black, while LCDs LED backlit can localize blackness for much deeper contrast.

If this is difficult for you to understand, just consider a dark scene in a movie as an example. The scene is a really dark black room with a closed door that lets some light through the bottom slot. An LED backlit LCD screen can handle this better than CCFL backlit screens, as the former can only include color for a portion around the door, allowing the rest of the screen to remain truly black.

Not every LED display is capable of locally dimming the screen as you just read.These are usually full array TVs (versus backlit edges) that support local dimming.

Additional information on the LCD

It is important to take extra care when cleaning LCD screens, be they TVs, smartphones, computer monitors, etc.

Most LCD monitors have a connection for HDMI and DVI cables. Some still support VGA cables, but this is much less common. If your computer’s graphics card only supports the older VGA connection, make sure to double check if there is an LCD monitor for it.You may need to purchase a VGA to HDMI or VGA to DVI adapter so that both ends can be used on each device.

What is the difference and differences between LED screens and LCD (LCD)

Modern man today is surrounded by many different screens and monitors. These are displays of TVs, computer monitors, screens of mobile gadgets. Of course, they all have different characteristics and features. What is the difference between LCD and LED? You will find the answer in our article.

It should be said right away that LED is an improved version of LCD.From this it comes out that LED screens are better than conventional LCD panels, they are brighter, the picture quality is clearer and more accurate.

Comparative characteristics of the presented types of screens

Let’s conduct a comparative analysis of the technical features of LCD and LED displays to understand their strengths and weaknesses.

  • Picture quality. LEDs have good color rendition and contrast, but this does not mean that LCDs are anything worse, they just lose a little to LEDs.They have a slightly lower color rendition and not so juicy brightness.
  • Electricity consumption. If saving is a matter of principle for you, then it is worth noting that the difference between LED and LCD in power consumption is 40%. LCD screens use more electricity.
  • Dimensions and parameters. If we take into account the indicators of weight and size, then LED panels win here too. They are slightly thinner than LCD monitors, and therefore lighter in weight. As a result, the stress on the wall is also less, which is very important especially in rooms.
  • Monitor lifespan. If we consider what is better than LCD or LED in terms of durability, then we will not surprise you here either, LED panels are more durable. There is a statistic that when working 8 hours a day, LED screens will last up to 30 years, while LCD screens – 20. Based on these data, it can be seen that LED video screens are more durable than LCD by about 30%.
  • Impact on the environment. In our time, environmental issues are especially relevant, so this aspect should not be overlooked.By disposing of both types of screens, LEDs have less environmental impact than LCD screens.
  • The cost of products. Well, here you can answer unequivocally that with the advent of LED screens on the market, the cost of LCD panels has dropped sharply. If you need a good, but budget option, then of course LCD screens win here.

What to choose?

We have explained to you how LED differs from LCD, and what to buy is up to you. If you need a screen, for example, in a television studio, for stage decoration and so on, then of course it is preferable to choose an LED screen.

It will look better in the frame, the viewers will have a clear picture. But if you are looking for a screen for private use or, say, for an office, then you can buy a liquid crystal display.

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *