Purchasing a TV was not challenging for the earlier generation because there was only one TV screen technology available, CRT.
Today, people are spoilt for choices because you have numerous technologies like LCD, LED, OLED, QLED, and many more to make your choice more difficult. This article discusses the various TV screen technologies witnessed in TVs over the years.
Before discussing each technology in detail, a tabular representation should make it easy for all.
|Cathode Ray Tube||Electron emitters shoot electrons at great speed through the CRT on the display screen to create images||Have quick response times Affordable than LCDs No question of dead pixels High native resolution 32-bit colors Ideal for watching all videos, including HD||Bulky instruments Compromises viewing screen It does not have a truly flat screen Compared to LCD, there is more radiation It consumes more power Image quality is satisfactory Now, an outdated technology|
|Plasma TV||It uses small cells containing plasma, an ionized gas, to respond to electric fields.||Do not need backlighting Produces better blacks Wider viewing angles, faster response time, and high refresh rates||More susceptible to burn-in and image retention Consumes more power Heavy compared to LCD monitors Now, an outdated technology|
|Liquid Crystal Display||Uses polarizing functions, liquid crystal molecules, and electrodes to produce images||Slimmer than CRTs 100% flat screens Less radiation than CRTs Light in weight Low power consumption Sharp display without glare Free from burn-in||Prone to dead pixels Lower response rates Comparatively expensive to CRTs Must be used at maximum resolution for best quality 8 bit color with a maximum of 16.7 million colors Not the ideal technology for viewing SD content|
|LCD TN Panels||It uses the perpendicular alignment of polarizing filters and twisted light polarization to create on and off modes.||Least expensive of all LCD panels Displays lowest input lag Supports high refresh rates||Limited viewing angles Weak color reproduction Limited contrast ratios|
|LCD IPS Panels||Electrodes are strategically arranged on the same plane and a single glass plate||Accurate and consistent color display from all viewing angles Stable response times Clear images and suited for touchscreen devices||Comparatively expensive Consumes more power Screen bleeding, at times|
|LCD PLS Panels||It is Samsung’s description of improved IPS panels||Improvement in viewing angles Enhanced brightness Reduction in production costs||Samsung proprietary technology|
|LCD AHVA Panels||An advancement over IPS and PLS||Supports higher refresh rates up to 144Hz Good viewing angles||Input lag IPS Glow|
|LCD VA Panels||Works on a similar principle as the TN panels but without twisting the polarization of light||Higher contrast ratio Comparatively affordable to IPS Displays black uniformity||Narrow viewing angle Slower response Lower color range|
|Light Emitting Diode – LED||LED backlighting for LCD panels instead of CCFL tubes||More brightness and contrast Environmentally friendly Thinner than other LCDs||Inconsistent contrast ratios Comparatively expensive to conventional lighting technologies Can shift color due to age|
|Quantum Dot LED – QLED||Uses an additional filter in the form of quantum dots to ensure better color filtering||Better contrast ratios Displays better blacks and whites High brightness levels||Passive technology It does not affect refresh rates and switch times Light bleeding|
|Organic LED – OLED||Display technology involving self-illuminating pixels instead of backlighting||Environmentally friendly Faster refresh rates Blur-free||Expensive Available on large TVs alone Lower lifespan|
|Micro-LED||Uses micro light-emitting diodes for self-illumination, similar to OLEDs||Better performance than the regular LEDs because of more light and brightness Extended lifespan Better contrast||Expensive technology At present, technology is in its initial stages|
|Mini LED||Uses smaller LEDs for backlighting||Easier to achieve mass production than micro LEDs Cheaper than an OLED panel It saves power and offers better brightness and black levels||Expensive compared to the regular LEDs Require more LEDs to light up the screen|
|Neo QLED||Mini QLED technology from Samsung||More than 5000 diodes on a single screen Precise dimming||Same as that of QLED, like light bleeding|
|NanoCell Technology||LG’s version of QLED technology||Produces good color output Ideal for gaming Best viewing angles||Inferior technology compared to OLED|
|QNED||Combination of Quantum Dot, NanoCell, and mini LED||More than 2500 dimming zones||LG proprietary technology, not available on other brands|
CRT – Cathode Ray Tube – An outdated technology.
CRT TVs are also known as Direct View TVs. In the early days of television, CRT was the only television screen technology available in the market. This technology persisted till the early years of the 21st century. Nowadays, no one manufactures CRT TVs. However, you will still find these TVs in few homes. They are also available in second-hand shops and P2P marketplaces.
As the technology is outdated, we will not go very deep into it. The Cathode Ray Tube is a vacuum tube that contains one or more electron emitters (also known as electron guns) and a fluorescent screen for viewing the images. The technology involves accelerating and deflecting the electron beams on the screen to create images.
The apparatus consists of an evacuated glass envelope that has to be large, dark, and deep to block most of the electron emissions from the emitter located at the far end of the tube. In the earlier days, manufacturers used lead glass to block electrons. Subsequently, they improvised vitrified strontium oxide glass for allowing better color visibility while blocking the electrons more efficiently.
These screens were bulky and fragile. Moreover, in the early days, they used to curve towards the exterior, a convex curve. It affected visibility because the curve restricts the viewing angle. Later on, there were improvements with such TVs coming with flat screens, however, nowhere near the flat-screen TVs available today.
Different types of CRT technology have been in use over the years. They include Shadow Mask CRT, Aperture Grill CRT (also called Trinitron), Monochrome CRT, Direct View Charactron CRT, CRT self-contained rear projection, and CRT front projection. However, today CRT TVs are obsolete.
DLP – Digital Light Processing
DLP is not a TV screen technology in the real sense. Instead, it is a video projector technology using a digital micromirror device.
Some DLPs come with TV tuners that make them a type of TV display. This technology has use in various applications like traditional static displays, interactive displays, and non-traditional embedded applications for use in medical, security, and other industries.
DLP is also used in standalone projectors in classrooms and businesses. In addition, this technology helps manufacture Rear Projection TVs, digital signs, and as a power source in SLA 3D printers.
Different types of DLP technology include DLP self-contained rear-projection and DLP front-projection. Laser self-contained rear projection is also a DLP variant.
Rear Projection TVs – Earliest technology
RPTVs were one of the earliest TVs produced, especially when it was impossible to produce tubes with large display sizes. In 1936, the maximum length of tube capable of fitting horizontally in a TV cabinet was around nine inches. Manufacturing 12-inch tubes were possible, but it involved complex technologies to fit it vertically and use mirrors for reflecting light. Thus, though it reduced the length of the TV, it increased its height. These mirror-lid TVs became obsolete long back, with CRT technology improving over time.
However, RPTVs did make a brief comeback in the early years of the 21st century as a suitable alternative to Plasma and LCD TVs. Compared to the conventional CRT TVs, these TVs were lighter. Like Plasma and LCD TVs, the screen was flat. However, the image quality was low. However, they phased out as quickly as they made a re-entry.
Plasma TV – Is also outdated today
Plasma TVs were flat panel display TVs using small cells containing plasma, an ionized gas that responds to electric fields.
Plasma TVs were initially large-screen TVs with a minimum size of 32 inches. Today, Plasma technology is obsolete as LCD and OLED have taken over. However, plasma TVs had their inherent advantages and disadvantages.
Plasma panels do not need any backlighting. Hence, the blacks produced by Plasma TVs are much better than those on LCD TVs. The color reproduction quality is similar to that of CRT TVs.
Compared to LCD TVs, plasma TVs allowed wider viewing angles. The high refresh rates and faster response times result in less motion blur in plasma TVs. They display uniformity in brightness levels.
Coming to the drawbacks, plasma TVs are susceptible to screen burn-in and image retention. Plasma TVs containing phosphors lose their luminosity over time. These TVs consume more electricity than conventional LCD TVs. Plasma TVs cannot work at altitudes over 6500 feet. Besides, plasma TVs are heavier than LCD TVs.
As a result, this technology was one of the most short-lived TV display technologies of all time. By 2014, all manufacturers phased out Plasma TVs from their line-up.
LCD – Liquid Crystal Display
LCD or Liquid Crystal Display is the most commonly used TV display technology even today in the times of OLED and QLED. Technology-wise, it is a flat-panel display that uses light-modulating properties of liquid crystals along with polarizers.
As these liquid crystals do not emit light directly, LCD depends on an external backlight or reflector to produce images. LCD is a superior technology to CRTs as it enabled manufacturers to reduce the thickness of the TV and make the TV screens available in large sizes.
Each LCD pixel constitutes a layer of molecules uniquely aligned between two transparent electrodes and two polarizing filters. Generally, these electrodes are made of Indium Tin Oxide. The polarization can be parallel or perpendicular.
The second filter would block the light passing through the first filter without a liquid crystal between the two filters. Therefore, before applying an electric field, the alignment at the surface of the electrodes determines the orientation of the liquid crystal molecules.
LCD panels are available in three types, depending on the alignment of the liquid crystal molecules inside the LCD and how they change on the application of voltage. Each panel has its benefits and drawbacks.
LCD TN – Twisted Nematic – Oldest LCD panels
The surface alignment directions are perpendicular in a TN (Twisted Nematic) Display. As a result, the molecules get twisted or arrange themselves in a helix. When light falls on these molecules, it induces a rotation of the polarization leading to the device appears gray. If you increase the voltage, the liquid crystal molecules in the center of the helix are untwisted. Therefore, the polarization will be perpendicular to the second filter. This filter blocks the light, and the pixel appears black.
The monochrome LCDs present in calculators, watches, and other devices function in the manner described above. Color LCD systems work on similar principles but use color filters to produce the RGB subpixels.
The primary drawback of TN panels was their narrow viewing angles, especially on the vertical axis. Besides, it does not offer substantial color reproduction. Therefore, these panels have low contrast ratios than IPS or VA panels. However, they have their advantages.
TN panels are the least expensive of the three. In addition, TN panels have the lowest input lag, around one millisecond. Hence, they can handle refresh rates as high as 240Hz comfortably. Therefore, gamers love these TN panels.
If you do not require much color reproduction or need deep viewing angles, the TN panel should be the most budget-friendly option.
LCD IPS – In-Plane Switching
LG coined the term In-Plane Switching. Samsung refers to the same technology as PLS (Plane-to-Line Switching), whereas AU Optronics refers to it as AHVA (Advanced Hyper-viewing angle). All these technologies are similar and comparable.
The polarizing filters in the TN panel had contrasting vertical and horizontal axes. In an IPS panel, they have axes in the same direction. However, the technology envisages treating the inner surfaces of the glass plates to align the bordering molecules at right angles to provide the twisted nematic effect.
While the molecular structure in IPS and TN panels is the same, the arrangement of the electrodes is different in an IPS. However, they are in the same plane and on a single glass plate. Hence, these panels are known as In-Plane Switching LCD panels.
The advantages of an IPS panel are that they display accurate and consistent color display from all viewing angles. In addition, they do not lighten when touched. Hence, they are excellent for touchscreen devices like tablets and smartphones. Furthermore, compared to TN panels, IPS offers clear images and stable response times.
However, there are some disadvantages, as well. Besides being more expensive than TN panels, the IPS panels consume up to 15% more power. While offering stable response times, it is consistently more than TN panels. Furthermore, IPS panels can be vulnerable to screen bleeding.
Hitachi was amongst the first users of this technology since 1996. They have developed various IPS technologies, like Super TFT, Super IPS, Advanced Super IPS, IPS Provectus, IPS Alpha, and IPS Alpha Next-Gen. LG adopted this technology later. It introduced several improvements to IPS, such as Horizontal IPS, Enhanced IPS, Professional IPS, and Advanced High-Performance IPS.
LCD PLS – Plane-To-Line Switching
LG is the prime manufacturer of IPS panels. However, Samsung offers a similar technology known as Plane-To-Line Switching (PLS). Samsung started using this technology because the AMOLED panels had challenges in realizing the full HD resolution on mobile devices.
Though the fundamental technology in IPS and PLS is the same, the PLS displays benefits like improvement in viewing angles, 10% enhancement in brightness, 15% reduction in production costs, better image quality, and a flexible panel.
LCD AHVA (Advanced Hyper-viewing Angle)
AU Optronics introduced the AHVA technology as an advancement over IPS and PLS. In addition, these panels are compatible with refresh rates as high as 144 Hz.
While IPS panels are better than TN panels, they are less efficient when measuring contrast ratios. Generally, screens with higher refresh rates have TN panels. But, the latest IPS panels also support high refresh rates. Compared to TN panels, IPS panels exhibit higher input lag. However, the latest LG Nano IPS UltraGear monitors come with a response time of 1ms.
However, there is a minor drawback known as the IPS Glow. It is a phenomenon that you experience when watching your TV from the most extreme viewing angle. You can witness the display’s backlight shining through the panel.
LCD VA (Vertical Alignment) Panels
The Vertical Alignment panel is an improvement over the TN panels. Here, the polarizing filters are aligned vertically and perpendicular to the glass substrate. As a result of passing the polarized light through the cells, the second set of liquid crystal molecules lying perpendicular to the first blocks the light to create a black state. However, on applying electric current, the cells align horizontally to allow the light to pass through.
The difference between VA and TN panels is the VA panels do not twist the light’s polarization. Instead, the liquid crystals are arranged parallel or perpendicular to the two polarizers. When in the off state, the crystals lie perpendicular to the polarizers. When switched on, they change direction and align horizontally to allow the light to go through them.
Compared to IPS panels, VA panels produce a higher contrast ratio of 3000:1 or 6000:1. In contrast, the IPS panel displays a contrast ratio of 1000:1. However, the VA panels are far inferior when comparing viewing angles.
Nevertheless, gamers love VA panels because they sit in front of the monitor when playing games.
The advantage of VA panels is that they offer contrast ratios three times better than IPS panels. In addition, they are affordable than IPS panels and deliver good black uniformity. However, they display a slow response time, low color range, and narrow viewing angles.
Samsung offers a better quality VA panel and names it SVA or Super Vertical Alignment. Samsung claims that it offers better viewing angles because it lays the liquid crystals in varying directions to allow the viewers to see the same colors even when viewing from wide angles. However, an IPS panel is always better as it offers the widest viewing angles of up to 178 degrees.
This table summarizes the distinctions and similarities between the three types of LCD panels.
|Parameters||Twisted Nematic||Vertical Alignment||In-Plane Switching|
|Performance||Fastest, with low response times, supports the highest refresh rates, low input lag, and minimum motion blur||Most extended response times, but capable of supporting the highest refresh rates than IPS||Compared to TN, the response times are slower but faster than VA. Generally, it does not support the highest refresh rates.|
|Display||Worst viewing angles of the three, color quality is also lower.||Better viewing angles than TN but displays best image depth and contrast||It offers the best viewing angles and color quality|
|Usage||Ideal for gaming||Good for general use||Best for professional users|
|Pricing||The Least expensive||Mid-range||The most expensive|
Different types of LCD technology are available. They include LCD Self-contained rear projection and LCD front-projection. Other LCD variants include Liquid Crystal on Silicon (LCoS) self-contained rear projection and LCoS front-projection.
Technologies offering a combination of LCD and CRT
SED – Surface Conduction Electron Emitter Display
This technology uses nanoscopic-scale electron emitters for energizing colored phosphors and producing an image. It consists of a matrix of CRTs, with each tube forming a sub-pixel on the screen in groups of three to form RGB pixels. Thus, SED combines the benefits of CRTs and LCDs. However, this technology is not much in use today.
FED – Field Emission Display
FED is similar to SEDs in many ways. The prime distinction is the use of large-area field electron emission instead of nanoscopic-scale electron emitters to strike the colored phosphor and produce an image.
As LCD technology started developing, SEDs and FEDs faded away in the first decade of the 21st century.
LED – Light Emitting Diode
LED is not a TV display technology but a backlighting arrangement for LCD Screens. Generally, LCD monitors use CCFL tubes for illuminating the liquid crystals. However, light Emitting Diode (LED) is a better illuminating agent than CCFL because of its inherent advantages.
An LED display uses an array of LEDs as pixels to illuminate the video display. The prime advantage of LED is its brightness quotient.
Today, all the LCD panels come with LED backlighting. As LEDs do not contain mercury, they are environmentally friendly. Besides, LED-LCD panels are thinner than the CCFL-illuminated LCD panels.
Edge Lit LED
LED displays come as either edge-lit displays or full-array displays, depending on the lighting configuration. An edge-lit LED features bulbs placed strategically around the screen’s perimeter.
When switched on, the lights from the edges illuminate the screen and distribute it across the screen using light guides. As the light source is placed at the edges, they are known as edge-lit LEDs.
Full Array LED
The full-array LED features LED lights embedded at specific intervals behind the display screen compared to the edge-lit LEDs. In addition, as the backlighting bulbs are arranged behind the screen, this technology can produce higher-quality images than their edge-lit LED counterparts.
Compared to the edge-lit LEDs, the full-array LEDs have more bulbs, resulting in better illumination.
QLED – Quantum Dot LED
For all the brightness that LEDs provide, LCD monitors have problems attaining HDR-level brightness because of incorrect polarization and color filters that block light.
However, Samsung has introduced a new technology that can overcome these issues. This technology is Quantum Dot technology.
Quantum dots layers comprise minute molecules that are placed between the blue blacklight and the polarization stage. These molecules absorb light and re-emit them in the color you want.
Generally, these quantum dots between the blue backlight and the polarization filter produce red and green colors that match the filters, allowing light to pass through them. Therefore, more light comes through instead of being blocked by color filters. It also eliminates the chances of colors slipping through the wrong subpixel and reduces crosstalk, ensuring better color reproduction of the LCD monitors.
Other types of quantum dots have been tried, such as replacing color filters entirely with quantum dots to allow more light to pass through. In addition, as LEDs produce bright light, quantum dots allow these LCDs to offer the brightest displays.
However, quantum dots have their drawbacks. They do not affect refresh rates or switch times. It is a passive technology that affects the color display and brightness alone.
Samsung TVs come with QLED panels. Besides, Panasonic is also planning to introduce QLED TVs in the future.
OLED – Organic Light Emitting Diode
When evaluating TV displays, OLED comes as a path-breaking technology. The best aspect of OLED is that there is no need for a backlight because it creates its own light. Hence, you have lighter and flatter screens with a display where each pixel self-illuminates, allowing you to control the images at the individual pixel level.
The technology involves placing organic films between semiconductors. On supplying electric current, each pixel can be switched on and off individually. Hence, it uses less power to create more brightness. Besides, it is also possible to create full black screens.
OLEDs can produce unlimited contrast. Hence, these screens are excellent for watching content featuring extreme darkness and brightness. This feature is one of the positives of OLED.
In addition, compared to the traditional panels, OLED is environmentally friendly because they do not require the use of greenhouse gas, Nitrogen Trifluoride, in their production.
They offer faster refresh rates and are blur-free. However, the significant demerit is that OLEDs are expensive. In addition, they have muted brightness levels of 1000 nits and are available in TV sizes 55, 65, and 77-inches alone.
LG is the only entity that manufactures OLED panels. However, you have LG, Sony, and Panasonic TVs using OLED panels in their TVs.
Micro LED – An emerging flat-panel display technology
Micro LED is an improvement of the standard OLED displays. It consists of an array of microscopic LEDs that form self-illuminating individual pixels.
Micro LEDs offer better contrast, are energy-efficient, and display better response times. You can find this technology more in AR glasses, VR headsets, smartphones, and smartwatches. Compared to OLED, micro LEDs have an extended lifespan because of their inorganic nature.
Mini LED display is better than the standard LEDs because it shrinks the LED molecules providing backlighting to LCD screens. Today, you have TV manufacturers like TCL, LG, Samsung, and Philips pursuing Mini LED backlighting technology. Apple is also using this technology in its new iPad Pro.
Mini LEDs are smaller than regular LEDs. Hence, they allow better backlighting and LCD panels to come as close as possible to OLEDs.
Neo QLED is Samsung’s way of describing Mini QLED. These TVs use a microlayer for guiding the mini LEDs through the quantum dots. Generally, it can accommodate as many as 5000 diodes for a single screen. As a result, you get more precise dimming.
NanoCell is a proprietary LG technology similar to Samsung’s QLED. It constitutes a filtering layer between the panel and the backlighting source. The purpose of NanoCell is to absorb specific wavelengths and purify the color output. Thus, it improves color depth.
However, the primary drawback of LG NanoCell technology is that it is expensive. Moreover, as it is a proprietary technology, it is not available on other TVs.
QNED – An LG proprietary technology
This pioneering display technology involves a combination of Quantum Dot technology, NanoCell, and Mini LED to deliver an innovative TV viewing experience.
This technology uses the Mini LED technique comprising minute LED lights to control the brightness levels and create a compelling contrast between the different screen areas. In addition, QNED TVs feature nearly 2500 dimming zones for limiting blooming and ensuring that light is appropriately directed.
LG has four QNED TVs in its LG TV 2021 range. Two of these TVs are 4K, and two are 8K TVs.
We have discussed various TV display technologies that manufacturers have used for producing TVs. Though you have many sub-technologies, they come under four primary categories, CRT, LCD, Plasma, and OLED. Today, CRT and Plasma technologies have all but disappeared. This age belongs to OLED and advanced forms of LED LCD technology. These technologies will remain until science invents new technologies for the better.
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Srinivasa is Vsbytes’s Editor-In-Chief. He Is A Microsoft Certified Solutions Expert And Has Been Interested In Computer Hardware, Software, And Gaming Right Since The Time He Was A Child.