lcd panel layer thickness brands
One of the advantages of designing a custom display is the ability to reduce your LCD display’s thickness by selecting a thin ITO glass; which is key to a thin LCD module.
The structure of the LCD is very basic, but a special glass called ITO glass is used in constructing the display. Three sides of the ITO glass are glued together with an adhesive or epoxy. Both the ITO glass and the nematic fluid used are transparent. There is a small gap of one or two millimeters between the top and bottom layer of glass. A nematic fluid is then injected between the layers. Finally, a cap is placed on the fourth side to keep the fluid from leaking out.
A polarizer is applied on both the top and bottom layer of glass. The polarizer on the top layer is always Transmissive, whereas the bottom layer can be Reflective, Transflective or Transmissive. For more details on the different types of polarizers, please read our article: LCD Polarizers.
ITO glass can be cut to custom dimensions, but smaller sized glass can add a significant cost increase to the overall cost of the LCD. The reason for the increased cost is the amount of labor and time required to add a polarizer to the small piece of glass.
Many times customers require the display to be as thin as possible; one method to achieve a thin LCD module is to select a thinner ITO glass. Keep in mind that the thinner the glass, the more expensive and the higher the fallout rate.
Note:Fallout rate does not mean failures of the LCD’s in the field; fallout is when the display fails on the manufacturing line. If the display fails in production, it is discarded before it is shipped to the customer.Once the display passes QA (Quality Assurance) it will operate normally for the life of the product.
It is possible to add a backlight to the monochrome display to make the display readable in low or no light conditions. The challenge of adding a LED backlight is that it increases the thickness of the LCD by as much as 5mm to 9mm.
In the photo above, a segmented LCD is combined with a LED backlight and backlight diffuser. A printed circuit board (PCB) is used to hold the assembly together. As the backlights name suggests, a light is placed behind the bottom layer of ITO glass.
Note: A backlight diffuser’s job function is similar to the lamp shade used on a table lamp. It disperses the light from each led to provide a more uniform appearance. Without the diffuser, there would be hot and cold spots on the display. A hot spot is where the backlight is too close to the LCD glass and it is overly bright; the area around the hot spot is dimmer and is referred to as a ‘cold spot’.
There are four methods to reduce the thickness of the LCD display/backlight combination; thereby creating a thin LCD module. However, these solutions do not apply to TFTs, VFDs, LEDs or OLEDs (Organic Light Emitting Diodes).
In the integration the backlight is sandwiched between the LCD and PCB. The LCD’s leads (pins) are then soldered to the PCB securely holding the backlight in place. This helps to create a thin LCD module.
Advantages of a PCB mounted LED backlight:The PCB combines the backlight and the LCD; this is great in applications that operating in environments of heavy vibration.
It is possible to build the PCB with only one or two layers to reduce the thickness, but current design practices call for a separate plane for power and ground. Also, a thinner board may not be as strong.
Another way to combine the LCD and the LED backlight is to use either a plastic clip to bind them together, or to use an epoxy or adhesive. There are advantages and disadvantages to both, but we suggest the plastic clip solution.
This method requires a one-time tooling fee to design and prototype a small, flexible plastic clip that holds the backlight and display together. The clip only adds a few pennies to the overall cost of the LCD combination.
This method is accomplished without any tooling cost and only adds a penny or two to the overall cost of the LCD assembly, but we do not recommend this approach.
An edge-lit display means that the LEDs are not placed behind the bottom layer of glass, but along the edge between the two layers of glass. This alone helps to create a thin LCD module.
Disadvantages to an Edge-lit display:One of the Challenges of this solution is that it increases the size of the overall display in the X and Y directions (Length and Width). Which means the sides of backlight will stick out beyond the LCD.
Side-lit displays work well for smaller size LCDs, but create hot spots around the edges if the display is too large. This is more evident with a white LED edge-lit; since white LEDs are much brighter than other colors and sometimes need to be dimmed to reduce their starkness.
EL backlights are AC (Alternating Current) driven, this requires an inverter either on the LCD or on the customers’ board. Inverters add extra cost and labor.
LEDs are DC (Direct Current) driven and do not require an inverter. Many times the voltage for the LED backlight is the same as for the LCD which means one less power supply is required.
While there are many different manufacturers of LCD monitors, the panels themselves are actually only manufactured by a relatively small selection of companies. The three main manufacturers tend to be Samsung, AU Optronics and LG.Display (previously LG.Philips), but there are also a range of other companies like Innolux and CPT which are used widely in the market. Below is a database of all the current panel modules manufactured in each size. These show the module number along with important information including panel technology and a detailed spec. This should provide a detailed list of panels used, and can give you some insight into what is used in any given LCD display.
Note:These are taken from manufacturer product documentation and panel resource websites. Specs are up to date to the best of our knowledge, and new panels will be added as and when they are produced. Where gaps are present, the detail is unknown or not listed in documentation. The colour depth specs are taken from the manufacturer, and so where they specify FRC and 8-bit etc, this is their listing. Absence of such in the table below does not necessarily mean they aren’t using FRC etc, just that this is how the manufacturer lists the spec on their site.
a line of extreme and ultra-narrow bezel LCD displays that provides a video wall solution for demanding requirements of 24x7 mission-critical applications and high ambient light environments
In both LCD and OLED displays, producing these cells – which are highly complex – is by far the most difficult element of the production process. Indeed, the complexity of these cells, combined with the levels of investment needed to achieve expertise in their production, explains why there are less than 30 companies in the whole world that can produce them. China, for instance, has invested more than 300 billion yuan (approximately $45 billion USD) in just one of these companies – BOE – over the past 14 years.
Panox Display has been involved in the display industry for many years and has built strong and long-term partner relationships with many of the biggest OLED and LCD panel manufacturers. As a result, we are able to offer our clients guaranteed access to display products from the biggest manufacturers.
LG Display was, until 2021, the No. 1 display panel manufacturer in the world. Owned by LG Group and headquartered in Seoul, South Korea, it has R&D, production, and trade institutions in China, Japan, South Korea, the United States, and Europe.
Founded in 2001, AUO – or AU Optronics – is the world’s leading TFT-LCD panel manufacturer (with a 16% market share) that designs, develops, and manufactures the world’s top three liquid crystal displays. With panels ranging from as small as 1.5 inches to 46 inches, it boasts one of the world"s few large-, medium -and small-sized product lines.
AUO offers advanced display integration solutions with innovative technologies, including 4K2K ultra-high resolution, 3D, ultra-thin, narrow bezel, transparent display, LTPS, OLED, and touch solutions. AOU has the most complete generation production line, ranging from 3.5G to 8.5G, offering panel products for a variety of LCD applications in a range of sizes, from as small as 1.2 inches to 71 inches.
Now Sharp is still top 10 TV brands all over the world. Just like BOE, Sharp produce LCDs in all kinds of size. Including small LCD (3.5 inch~9.1 inch), medium LCD (10.1 ~27 inch), large LCD (31.5~110 inch). Sharp LCD has been used on Iphone series for a long time.
Beside those current LCDs, the industrial LCD of Sharp is also excellent and widely used in public facilities, factories, and vehicles. The Sharp industrial LCD, just means solid, high brightness, super long working time, highest stability.
Since its establishment, Truly Semiconductors has focused on researching, developing, and manufacturing liquid crystal flat panel displays. Now, after twenty years of development, it is the biggest small- and medium-sized flat panel display manufacturer in China.
Truly’s factory in Shanwei City is enormous, covering an area of 1 million square meters, with a net housing area of more than 100,000 square meters. It includes five LCD production lines, one OLED production line, three touch screen production lines, and several COG, LCM, MDS, CCM, TAB, and SMT production lines.
Its world-class production lines produce LCD displays, liquid crystal display modules (LCMs), OLED displays, resistive and capacitive touch screens (touch panels), micro camera modules (CCMs), and GPS receiving modules, with such products widely used in the smartphone, automobile, and medical industries. The LCD products it offers include TFT, TN, Color TN with Black Mark (TN type LCD display for onboard machines), STN, FSTN, 65K color, and 262K color or above CSTN, COG, COF, and TAB modules.
In its early days, Innolux attached great importance to researching and developing new products. Mobile phones, portable and mounted DVD players, digital cameras, games consoles, PDA LCDs, and other star products were put into mass production and quickly captured the market, winning the company considerable market share.
Looking forward to the future, the group of photoelectric will continue to deep LCD display field, is committed to the development of plane display core technology, make good use of global operations mechanism and depth of division of labor, promise customers high-quality products and services, become the world"s top display system suppliers, in 2006 in the global mobile phone color display market leader, become "Foxconn technology" future sustained rapid growth of the engine.
Founded in June 1998, Hannstar specializes in producing thin-film transistor liquid crystal display panels, mainly for use in monitors, notebook displays and televisions. It was the first company in Taiwan to adopt the world’s top ultra-wide perspective technology (AS-IPS).
The company has three LCD factories and one LCM factory. It has acquired state-of-the-art TFT-LCD manufacturing technology, which enables it to achieve the highest efficiency in the mass production of thin-film transistor liquid crystal display production technology. Its customers include many of the biggest and most well-known electronics companies and computer manufacturers in Taiwan and overseas.
TCL CSOT – short for TCL China Star Optoelectronics Technology (TCL CSOT) – was founded in 2009 and is an innovative technology enterprise that focuses on the production of semiconductor displays. As one of the global leaders in semiconductor display market, it has bases in Shenzhen, Wuhan, Huizhou, Suzhou, Guangzhou, and India, with nine panel production lines and five large modules bases.
TCL CSOT actively produces Mini LED, Micro LED, flexible OLED, printing OLED, and other new display technologies. Its product range is vast – including large, medium, and small panels and touch modules, electronic whiteboards, splicing walls, automotive displays, gaming monitors, and other high-end display application fields – which has enabled it to become a leading player in the global panel industry.
In the first quarter of 2022, TCL CSOT’s TV panels ranked second in the market, 55 inches, 65 " and 75 inches second, 8K, 120Hz first, the first, interactive whiteboard and digital sign plate; LTPS flat panel, the second, LTPS and flexible OLED fourth.
EDO (also known as EverDisplay Optonics) was founded in October 2012 and focuses on the production of small- and medium-sized high-resolution AMOLED semiconductor display panels.
Tianma Microelectronics was founded in 1983 and listed on the Shenzhen Stock Exchange in 1995. It is a high-tech enterprise specializing in the production of liquid crystal displays (LCD) and liquid crystal display modules (LCM).
After more than 30 years of development, it has grown into a large publicly listed company integrating LCD research and development, design, production, sales, and servicing. Over the years, it has expanded by investing in the construction of STN-LCD, CSTN-LCD, TFT-LCD and CF production lines and module factories across China (with locations in Shenzhen, Shanghai, Chengdu, Wuhan and Xiamen), as well R&D centers and offices in Europe, Japan, South Korea and the United States.
The company"s marketing network is all over the world, and its products are widely used in mobile phones, MP3/MP4 players, vehicle displays, instrumentation, household appliances, and other fields. In terms of technical level, product quality, product grade, and market share, it ranks at the forefront of the domestic industry and has become a leading enterprise in the field of small- and medium-sized displays.
JDI (Japan Display Inc.) was established on November 15, 2011, as a joint venture between the Industrial Innovation Corporation, Sony, Hitachi, and Toshiba. It is dedicated to the production and development of small-sized displays. It mainly produces small- and medium-sized LCD display panels for use in the automotive, medical, and industrial fields, as well as personal devices including smartphones, tablets, and wearables.
Although Sony’s TVs use display panels from TCL CSOT (VA panel), Samsung. Sony still produces the world’s best micro-OLED display panels. Sony has many micro OLED model such as 0.23 inch, 0.39 inch, 0.5 inch, 0.64 inch, 0.68 inch, 0.71 inch. Panox Display used to test and sell many of them, compare to other micro OLED manufacuturers, Sony`s micro OLEDs are with the best image quality and highest brightness (3000 nits max).
Glass substrate with ITO electrodes. The shapes of these electrodes will determine the shapes that will appear when the LCD is switched ON. Vertical ridges etched on the surface are smooth.
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directlybacklight or reflector to produce images in color or monochrome.seven-segment displays, as in a digital clock, are all good examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs can either be normally on (positive) or off (negative), depending on the polarizer arrangement. For example, a character positive LCD with a backlight will have black lettering on a background that is the color of the backlight, and a character negative LCD will have a black background with the letters being of the same color as the backlight. Optical filters are added to white on blue LCDs to give them their characteristic appearance.
LCDs are used in a wide range of applications, including LCD televisions, computer monitors, instrument panels, aircraft cockpit displays, and indoor and outdoor signage. Small LCD screens are common in LCD projectors and portable consumer devices such as digital cameras, watches, calculators, and mobile telephones, including smartphones. LCD screens have replaced heavy, bulky and less energy-efficient cathode-ray tube (CRT) displays in nearly all applications. The phosphors used in CRTs make them vulnerable to image burn-in when a static image is displayed on a screen for a long time, e.g., the table frame for an airline flight schedule on an indoor sign. LCDs do not have this weakness, but are still susceptible to image persistence.
Each pixel of an LCD typically consists of a layer of molecules aligned between two transparent electrodes, often made of Indium-Tin oxide (ITO) and two polarizing filters (parallel and perpendicular polarizers), the axes of transmission of which are (in most of the cases) perpendicular to each other. Without the liquid crystal between the polarizing filters, light passing through the first filter would be blocked by the second (crossed) polarizer. Before an electric field is applied, the orientation of the liquid-crystal molecules is determined by the alignment at the surfaces of electrodes. In a twisted nematic (TN) device, the surface alignment directions at the two electrodes are perpendicular to each other, and so the molecules arrange themselves in a helical structure, or twist. This induces the rotation of the polarization of the incident light, and the device appears gray. If the applied voltage is large enough, the liquid crystal molecules in the center of the layer are almost completely untwisted and the polarization of the incident light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the voltage applied across the liquid crystal layer in each pixel, light can be allowed to pass through in varying amounts thus constituting different levels of gray.
The chemical formula of the liquid crystals used in LCDs may vary. Formulas may be patented.Sharp Corporation. The patent that covered that specific mixture expired.
Most color LCD systems use the same technique, with color filters used to generate red, green, and blue subpixels. The LCD color filters are made with a photolithography process on large glass sheets that are later glued with other glass sheets containing a TFT array, spacers and liquid crystal, creating several color LCDs that are then cut from one another and laminated with polarizer sheets. Red, green, blue and black photoresists (resists) are used. All resists contain a finely ground powdered pigment, with particles being just 40 nanometers across. The black resist is the first to be applied; this will create a black grid (known in the industry as a black matrix) that will separate red, green and blue subpixels from one another, increasing contrast ratios and preventing light from leaking from one subpixel onto other surrounding subpixels.Super-twisted nematic LCD, where the variable twist between tighter-spaced plates causes a varying double refraction birefringence, thus changing the hue.
LCD in a Texas Instruments calculator with top polarizer removed from device and placed on top, such that the top and bottom polarizers are perpendicular. As a result, the colors are inverted.
The optical effect of a TN device in the voltage-on state is far less dependent on variations in the device thickness than that in the voltage-off state. Because of this, TN displays with low information content and no backlighting are usually operated between crossed polarizers such that they appear bright with no voltage (the eye is much more sensitive to variations in the dark state than the bright state). As most of 2010-era LCDs are used in television sets, monitors and smartphones, they have high-resolution matrix arrays of pixels to display arbitrary images using backlighting with a dark background. When no image is displayed, different arrangements are used. For this purpose, TN LCDs are operated between parallel polarizers, whereas IPS LCDs feature crossed polarizers. In many applications IPS LCDs have replaced TN LCDs, particularly in smartphones. Both the liquid crystal material and the alignment layer material contain ionic compounds. If an electric field of one particular polarity is applied for a long period of time, this ionic material is attracted to the surfaces and degrades the device performance. This is avoided either by applying an alternating current or by reversing the polarity of the electric field as the device is addressed (the response of the liquid crystal layer is identical, regardless of the polarity of the applied field).
Displays for a small number of individual digits or fixed symbols (as in digital watches and pocket calculators) can be implemented with independent electrodes for each segment.alphanumeric or variable graphics displays are usually implemented with pixels arranged as a matrix consisting of electrically connected rows on one side of the LC layer and columns on the other side, which makes it possible to address each pixel at the intersections. The general method of matrix addressing consists of sequentially addressing one side of the matrix, for example by selecting the rows one-by-one and applying the picture information on the other side at the columns row-by-row. For details on the various matrix addressing schemes see passive-matrix and active-matrix addressed LCDs.
LCDs are manufactured in cleanrooms borrowing techniques from semiconductor manufacturing and using large sheets of glass whose size has increased over time. Several displays are manufactured at the same time, and then cut from the sheet of glass, also known as the mother glass or LCD glass substrate. The increase in size allows more displays or larger displays to be made, just like with increasing wafer sizes in semiconductor manufacturing. The glass sizes are as follows:
Until Gen 8, manufacturers would not agree on a single mother glass size and as a result, different manufacturers would use slightly different glass sizes for the same generation. Some manufacturers have adopted Gen 8.6 mother glass sheets which are only slightly larger than Gen 8.5, allowing for more 50 and 58 inch LCDs to be made per mother glass, specially 58 inch LCDs, in which case 6 can be produced on a Gen 8.6 mother glass vs only 3 on a Gen 8.5 mother glass, significantly reducing waste.AGC Inc., Corning Inc., and Nippon Electric Glass.
In 1888,Friedrich Reinitzer (1858–1927) discovered the liquid crystalline nature of cholesterol extracted from carrots (that is, two melting points and generation of colors) and published his findings at a meeting of the Vienna Chemical Society on May 3, 1888 (F. Reinitzer: Beiträge zur Kenntniss des Cholesterins, Monatshefte für Chemie (Wien) 9, 421–441 (1888)).Otto Lehmann published his work "Flüssige Kristalle" (Liquid Crystals). In 1911, Charles Mauguin first experimented with liquid crystals confined between plates in thin layers.
In 1922, Georges Friedel described the structure and properties of liquid crystals and classified them in three types (nematics, smectics and cholesterics). In 1927, Vsevolod Frederiks devised the electrically switched light valve, called the Fréedericksz transition, the essential effect of all LCD technology. In 1936, the Marconi Wireless Telegraph company patented the first practical application of the technology, "The Liquid Crystal Light Valve". In 1962, the first major English language publication Molecular Structure and Properties of Liquid Crystals was published by Dr. George W. Gray.RCA found that liquid crystals had some interesting electro-optic characteristics and he realized an electro-optical effect by generating stripe-patterns in a thin layer of liquid crystal material by the application of a voltage. This effect is based on an electro-hydrodynamic instability forming what are now called "Williams domains" inside the liquid crystal.
In the late 1960s, pioneering work on liquid crystals was undertaken by the UK"s Royal Radar Establishment at Malvern, England. The team at RRE supported ongoing work by George William Gray and his team at the University of Hull who ultimately discovered the cyanobiphenyl liquid crystals, which had correct stability and temperature properties for application in LCDs.
The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968.dynamic scattering mode (DSM) LCD that used standard discrete MOSFETs.
On December 4, 1970, the twisted nematic field effect (TN) in liquid crystals was filed for patent by Hoffmann-LaRoche in Switzerland, (Swiss patent No. 532 261) with Wolfgang Helfrich and Martin Schadt (then working for the Central Research Laboratories) listed as inventors.Brown, Boveri & Cie, its joint venture partner at that time, which produced TN displays for wristwatches and other applications during the 1970s for the international markets including the Japanese electronics industry, which soon produced the first digital quartz wristwatches with TN-LCDs and numerous other products. James Fergason, while working with Sardari Arora and Alfred Saupe at Kent State University Liquid Crystal Institute, filed an identical patent in the United States on April 22, 1971.ILIXCO (now LXD Incorporated), produced LCDs based on the TN-effect, which soon superseded the poor-quality DSM types due to improvements of lower operating voltages and lower power consumption. Tetsuro Hama and Izuhiko Nishimura of Seiko received a US patent dated February 1971, for an electronic wristwatch incorporating a TN-LCD.
In 1972, the concept of the active-matrix thin-film transistor (TFT) liquid-crystal display panel was prototyped in the United States by T. Peter Brody"s team at Westinghouse, in Pittsburgh, Pennsylvania.Westinghouse Research Laboratories demonstrated the first thin-film-transistor liquid-crystal display (TFT LCD).high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.active-matrix liquid-crystal display (AM LCD) in 1974, and then Brody coined the term "active matrix" in 1975.
In 1972 North American Rockwell Microelectronics Corp introduced the use of DSM LCDs for calculators for marketing by Lloyds Electronics Inc, though these required an internal light source for illumination.Sharp Corporation followed with DSM LCDs for pocket-sized calculators in 1973Seiko and its first 6-digit TN-LCD quartz wristwatch, and Casio"s "Casiotron". Color LCDs based on Guest-Host interaction were invented by a team at RCA in 1968.TFT LCDs similar to the prototypes developed by a Westinghouse team in 1972 were patented in 1976 by a team at Sharp consisting of Fumiaki Funada, Masataka Matsuura, and Tomio Wada,
In 1983, researchers at Brown, Boveri & Cie (BBC) Research Center, Switzerland, invented the passive matrix-addressed LCDs. H. Amstutz et al. were listed as inventors in the corresponding patent applications filed in Switzerland on July 7, 1983, and October 28, 1983. Patents were granted in Switzerland CH 665491, Europe EP 0131216,
The first color LCD televisions were developed as handheld televisions in Japan. In 1980, Hattori Seiko"s R&D group began development on color LCD pocket televisions.Seiko Epson released the first LCD television, the Epson TV Watch, a wristwatch equipped with a small active-matrix LCD television.dot matrix TN-LCD in 1983.Citizen Watch,TFT LCD.computer monitors and LCD televisions.3LCD projection technology in the 1980s, and licensed it for use in projectors in 1988.compact, full-color LCD projector.
In 1990, under different titles, inventors conceived electro optical effects as alternatives to twisted nematic field effect LCDs (TN- and STN- LCDs). One approach was to use interdigital electrodes on one glass substrate only to produce an electric field essentially parallel to the glass substrates.Germany by Guenter Baur et al. and patented in various countries.Hitachi work out various practical details of the IPS technology to interconnect the thin-film transistor array as a matrix and to avoid undesirable stray fields in between pixels.
Hitachi also improved the viewing angle dependence further by optimizing the shape of the electrodes (Super IPS). NEC and Hitachi become early manufacturers of active-matrix addressed LCDs based on the IPS technology. This is a milestone for implementing large-screen LCDs having acceptable visual performance for flat-panel computer monitors and television screens. In 1996, Samsung developed the optical patterning technique that enables multi-domain LCD. Multi-domain and In Plane Switching subsequently remain the dominant LCD designs through 2006.South Korea and Taiwan,
In 2007 the image quality of LCD televisions surpassed the image quality of cathode-ray-tube-based (CRT) TVs.LCD TVs were projected to account 50% of the 200 million TVs to be shipped globally in 2006, according to Displaybank.Toshiba announced 2560 × 1600 pixels on a 6.1-inch (155 mm) LCD panel, suitable for use in a tablet computer,
In 2016, Panasonic developed IPS LCDs with a contrast ratio of 1,000,000:1, rivaling OLEDs. This technology was later put into mass production as dual layer, dual panel or LMCL (Light Modulating Cell Layer) LCDs. The technology uses 2 liquid crystal layers instead of one, and may be used along with a mini-LED backlight and quantum dot sheets.
Since LCDs produce no light of their own, they require external light to produce a visible image.backlight. Active-matrix LCDs are almost always backlit.Transflective LCDs combine the features of a backlit transmissive display and a reflective display.
CCFL: The LCD panel is lit either by two cold cathode fluorescent lamps placed at opposite edges of the display or an array of parallel CCFLs behind larger displays. A diffuser (made of PMMA acrylic plastic, also known as a wave or light guide/guiding plateinverter to convert whatever DC voltage the device uses (usually 5 or 12 V) to ≈1000 V needed to light a CCFL.
EL-WLED: The LCD panel is lit by a row of white LEDs placed at one or more edges of the screen. A light diffuser (light guide plate, LGP) is then used to spread the light evenly across the whole display, similarly to edge-lit CCFL LCD backlights. The diffuser is made out of either PMMA plastic or special glass, PMMA is used in most cases because it is rugged, while special glass is used when the thickness of the LCD is of primary concern, because it doesn"t expand as much when heated or exposed to moisture, which allows LCDs to be just 5mm thick. Quantum dots may be placed on top of the diffuser as a quantum dot enhancement film (QDEF, in which case they need a layer to be protected from heat and humidity) or on the color filter of the LCD, replacing the resists that are normally used.
WLED array: The LCD panel is lit by a full array of white LEDs placed behind a diffuser behind the panel. LCDs that use this implementation will usually have the ability to dim or completely turn off the LEDs in the dark areas of the image being displayed, effectively increasing the contrast ratio of the display. The precision with which this can be done will depend on the number of dimming zones of the display. The more dimming zones, the more precise the dimming, with less obvious blooming artifacts which are visible as dark grey patches surrounded by the unlit areas of the LCD. As of 2012, this design gets most of its use from upscale, larger-screen LCD televisions.
RGB-LED array: Similar to the WLED array, except the panel is lit by a full array of RGB LEDs. While displays lit with white LEDs usually have a poorer color gamut than CCFL lit displays, panels lit with RGB LEDs have very wide color gamuts. This implementation is most popular on professional graphics editing LCDs. As of 2012, LCDs in this category usually cost more than $1000. As of 2016 the cost of this category has drastically reduced and such LCD televisions obtained same price levels as the former 28" (71 cm) CRT based categories.
Monochrome LEDs: such as red, green, yellow or blue LEDs are used in the small passive monochrome LCDs typically used in clocks, watches and small appliances.
Today, most LCD screens are being designed with an LED backlight instead of the traditional CCFL backlight, while that backlight is dynamically controlled with the video information (dynamic backlight control). The combination with the dynamic backlight control, invented by Philips researchers Douglas Stanton, Martinus Stroomer and Adrianus de Vaan, simultaneously increases the dynamic range of the display system (also marketed as HDR, high dynamic range television or FLAD, full-area local area dimming).
The LCD backlight systems are made highly efficient by applying optical films such as prismatic structure (prism sheet) to gain the light into the desired viewer directions and reflective polarizing films that recycle the polarized light that was formerly absorbed by the first polarizer of the LCD (invented by Philips researchers Adrianus de Vaan and Paulus Schaareman),
A pink elastomeric connector mating an LCD panel to circuit board traces, shown next to a centimeter-scale ruler. The conductive and insulating layers in the black stripe are very small.
A standard television receiver screen, a modern LCD panel, has over six million pixels, and they are all individually powered by a wire network embedded in the screen. The fine wires, or pathways, form a grid with vertical wires across the whole screen on one side of the screen and horizontal wires across the whole screen on the other side of the screen. To this grid each pixel has a positive connection on one side and a negative connection on the other side. So the total amount of wires needed for a 1080p display is 3 x 1920 going vertically and 1080 going horizontally for a total of 6840 wires horizontally and vertically. That"s three for red, green and blue and 1920 columns of pixels for each color for a total of 5760 wires going vertically and 1080 rows of wires going horizontally. For a panel that is 28.8 inches (73 centimeters) wide, that means a wire density of 200 wires per inch along the horizontal edge.
The LCD panel is powered by LCD drivers that are carefully matched up with the edge of the LCD panel at the factory level. The drivers may be installed using several methods, the most common of which are COG (Chip-On-Glass) and TAB (Tape-automated bonding) These same principles apply also for smartphone screens that are much smaller than TV screens.anisotropic conductive film or, for lower densities, elastomeric connectors.
Monochrome and later color passive-matrix LCDs were standard in most early laptops (although a few used plasma displaysGame Boyactive-matrix became standard on all laptops. The commercially unsuccessful Macintosh Portable (released in 1989) was one of the first to use an active-matrix display (though still monochrome). Passive-matrix LCDs are still used in the 2010s for applications less demanding than laptop computers and TVs, such as inexpensive calculators. In particular, these are used on portable devices where less information content needs to be displayed, lowest power consumption (no backlight) and low cost are desired or readability in direct sunlight is needed.
STN LCDs have to be continuously refreshed by alternating pulsed voltages of one polarity during one frame and pulses of opposite polarity during the next frame. Individual pixels are addressed by the corresponding row and column circuits. This type of display is called response times and poor contrast are typical of passive-matrix addressed LCDs with too many pixels and driven according to the "Alt & Pleshko" drive scheme. Welzen and de Vaan also invented a non RMS drive scheme enabling to drive STN displays with video rates and enabling to show smooth moving video images on an STN display.
Bistable LCDs do not require continuous refreshing. Rewriting is only required for picture information changes. In 1984 HA van Sprang and AJSM de Vaan invented an STN type display that could be operated in a bistable mode, enabling extremely high resolution images up to 4000 lines or more using only low voltages.
High-resolution color displays, such as modern LCD computer monitors and televisions, use an active-matrix structure. A matrix of thin-film transistors (TFTs) is added to the electrodes in contact with the LC layer. Each pixel has its own dedicated transistor, allowing each column line to access one pixel. When a row line is selected, all of the column lines are connected to a row of pixels and voltages corresponding to the picture information are driven onto all of the column lines. The row line is then deactivated and the next row line is selected. All of the row lines are selected in sequence during a refresh operation. Active-matrix addressed displays look brighter and sharper than passive-matrix addressed displays of the same size, and generally have quicker response times, producing much better images. Sharp produces bistable reflective LCDs with a 1-bit SRAM cell per pixel that only requires small amounts of power to maintain an image.
Segment LCDs can also have color by using Field Sequential Color (FSC LCD). This kind of displays have a high speed passive segment LCD panel with an RGB backlight. The backlight quickly changes color, making it appear white to the naked eye. The LCD panel is synchronized with the backlight. For example, to make a segment appear red, the segment is only turned ON when the backlight is red, and to make a segment appear magenta, the segment is turned ON when the backlight is blue, and it continues to be ON while the backlight becomes red, and it turns OFF when the backlight becomes green. To make a segment appear black, the segment is always turned ON. An FSC LCD divides a color image into 3 images (one Red, one Green and one Blue) and it displays them in order. Due to persistence of vision, the 3 monochromatic images appear as one color image. An FSC LCD needs an LCD panel with a refresh rate of 180 Hz, and the response time is reduced to just 5 milliseconds when compared with normal STN LCD panels which have a response time of 16 milliseconds.
Samsung introduced UFB (Ultra Fine & Bright) displays back in 2002, utilized the super-birefringent effect. It has the luminance, color gamut, and most of the contrast of a TFT-LCD, but only consumes as much power as an STN display, according to Samsung. It was being used in a variety of Samsung cellular-telephone models produced until late 2006, when Samsung stopped producing UFB displays. UFB displays were also used in certain models of LG mobile phones.
Twisted nematic displays contain liquid crystals that twist and untwist at varying degrees to allow light to pass through. When no voltage is applied to a TN liquid crystal cell, polarized light passes through the 90-degrees twisted LC layer. In proportion to the voltage applied, the liquid crystals untwist changing the polarization and blocking the light"s path. By properly adjusting the level of the voltage almost any gray level or transmission can be achieved.
In-plane switching is an LCD technology that aligns the liquid crystals in a plane parallel to the glass substrates. In this method, the electrical field is applied through opposite electrodes on the same glass substrate, so that the liquid crystals can be reoriented (switched) essentially in the same plane, although fringe fields inhibit a homogeneous reorientation. This requires two transistors for each pixel instead of the single transistor needed for a standard thin-film transistor (TFT) display. The IPS technology is used in everything from televisions, computer monitors, and even wearable devices, especially almost all LCD smartphone panels are IPS/FFS mode. IPS displays belong to the LCD panel family screen types. The other two types are VA and TN. Before LG Enhanced IPS was introduced in 2001 by Hitachi as 17" monitor in Market, the additional transistors resulted in blocking more transmission area, thus requiring a brighter backlight and consuming more power, making this type of display less desirable for notebook computers. Panasonic Himeji G8.5 was using an enhanced version of IPS, also LGD in Korea, then currently the world biggest LCD panel manufacture BOE in China is also IPS/FFS mode TV panel.
In 2015 LG Display announced the implementation of a new technology called M+ which is the addition of white subpixel along with the regular RGB dots in their IPS panel technology.
In 2011, LG claimed the smartphone LG Optimus Black (IPS LCD (LCD NOVA)) has the brightness up to 700 nits, while the competitor has only IPS LCD with 518 nits and double an active-matrix OLED (AMOLED) display with 305 nits. LG also claimed the NOVA display to be 50 percent more efficient than regular LCDs and to consume only 50 percent of the power of AMOLED displays when producing white on screen.
This pixel-layout is found in S-IPS LCDs. A chevron shape is used to widen the viewing cone (range of viewing directions with good contrast and low color shift).
Vertical-alignment displays are a form of LCDs in which the liquid crystals naturally align vertically to the glass substrates. When no voltage is applied, the liquid crystals remain perpendicular to the substrate, creating a black display between crossed polarizers. When voltage is applied, the liquid crystals shift to a tilted position, allowing light to pass through and create a gray-scale display depending on the amount of tilt generated by the electric field. It has a deeper-black background, a higher contrast ratio, a wider viewing angle, and better image quality at extreme temperatures than traditional twisted-nematic displays.
Blue phase mode LCDs have been shown as engineering samples early in 2008, but they are not in mass-production. The physics of blue phase mode LCDs suggest that very short switching times (≈1 ms) can be achieved, so time sequential color control can possibly be realized and expensive color filters would be obsolete.
Some LCD panels have defective transistors, causing permanently lit or unlit pixels which are commonly referred to as stuck pixels or dead pixels respectively. Unlike integrated circuits (ICs), LCD panels with a few defective transistors are usually still usable. Manufacturers" policies for the acceptable number of defective pixels vary greatly. At one point, Samsung held a zero-tolerance policy for LCD monitors sold in Korea.ISO 13406-2 standard.
Dead pixel policies are often hotly debated between manufacturers and customers. To regulate the acceptability of defects and to protect the end user, ISO released the ISO 13406-2 standard,ISO 9241, specifically ISO-9241-302, 303, 305, 307:2008 pixel defects. However, not every LCD manufacturer conforms to the ISO standard and the ISO standard is quite often interpreted in different ways. LCD panels are more likely to have defects than most ICs due to their larger size. For example, a 300 mm SVGA LCD has 8 defects and a 150 mm wafer has only 3 defects. However, 134 of the 137 dies on the wafer will be acceptable, whereas rejection of the whole LCD panel would be a 0% yield. In recent years, quality control has been improved. An SVGA LCD panel with 4 defective pixels is usually considered defective and customers can request an exchange for a new one.
Some manufacturers, notably in South Korea where some of the largest LCD panel manufacturers, such as LG, are located, now have a zero-defective-pixel guarantee, which is an extra screening process which can then determine "A"- and "B"-grade panels.clouding (or less commonly mura), which describes the uneven patches of changes in luminance. It is most visible in dark or black areas of displayed scenes.
The zenithal bistable device (ZBD), developed by Qinetiq (formerly DERA), can retain an image without power. The crystals may exist in one of two stable orientations ("black" and "white") and power is only required to change the image. ZBD Displays is a spin-off company from QinetiQ who manufactured both grayscale and color ZBD devices. Kent Displays has also developed a "no-power" display that uses polymer stabilized cholesteric liquid crystal (ChLCD). In 2009 Kent demonstrated the use of a ChLCD to cover the entire surface of a mobile phone, allowing it to change colors, and keep that color even when power is removed.
In 2004, researchers at the University of Oxford demonstrated two new types of zero-power bistable LCDs based on Zenithal bistable techniques.e.g., BiNem technology, are based mainly on the surface properties and need specific weak anchoring materials.
Resolution The resolution of an LCD is expressed by the number of columns and rows of pixels (e.g., 1024×768). Each pixel is usually composed 3 sub-pixels, a red, a green, and a blue one. This had been one of the few features of LCD performance that remained uniform among different designs. However, there are newer designs that share sub-pixels among pixels and add Quattron which attempt to efficiently increase the perceived resolution of a display without increasing the actual resolution, to mixed results.
Spatial performance: For a computer monitor or some other display that is being viewed from a very close distance, resolution is often expressed in terms of dot pitch or pixels per inch, which is consistent with the printing industry. Display density varies per application, with televisions generally having a low density for long-distance viewing and portable devices having a high density for close-range detail. The Viewing Angle of an LCD may be important depending on the display and its usage, the limitations of certain display technologies mean the display only displays accurately at certain angles.
Temporal performance: the temporal resolution of an LCD is how well it can display changing images, or the accuracy and the number of times per second the display draws the data it is being given. LCD pixels do not flash on/off between frames, so LCD monitors exhibit no refresh-induced flicker no matter how low the refresh rate.
Brightness and contrast ratio: Contrast ratio is the ratio of the brightness of a full-on pixel to a full-off pixel. The LCD itself is only a light valve and does not generate light; the light comes from a backlight that is either fluorescent or a set of LEDs. Brightness is usually stated as the maximum light output of the LCD, which can vary greatly based on the transparency of the LCD and the brightness of the backlight. Brighter backlight allows stronger contrast and higher dynamic range (HDR displays are graded in peak luminance), but there is always a trade-off between brightness and power consumption.
Usually no refresh-rate flicker, because the LCD pixels hold their state between refreshes (which are usually done at 200 Hz or faster, regardless of the input refresh rate).
No theoretical resolution limit. When multiple LCD panels are used together to create a single canvas, each additional panel increases the total resolution of the display, which is commonly called stacked resolution.
LCDs can be made transparent and flexible, but they cannot emit light without a backlight like OLED and microLED, which are other technologies that can also be made flexible and transparent.
As an inherently digital device, the LCD can natively display digital data from a DVI or HDMI connection without requiring conversion to analog. Some LCD panels have native fiber optic inputs in addition to DVI and HDMI.
Limited viewing angle in some older or cheaper monitors, causing color, saturation, contrast and brightness to vary with user position, even within the intended viewing angle. Special films can be used to increase the viewing angles of LCDs.
As of 2012, most implementations of LCD backlighting use pulse-width modulation (PWM) to dim the display,CRT monitor at 85 Hz refresh rate would (this is because the entire screen is strobing on and off rather than a CRT"s phosphor sustained dot which continually scans across the display, leaving some part of the display always lit), causing severe eye-strain for some people.LED-backlit monitors, because the LEDs switch on and off faster than a CCFL lamp.
Fixed bit depth (also called color depth). Many cheaper LCDs are only able to display 262144 (218) colors. 8-bit S-IPS panels can display 16 million (224) colors and have significantly better black level, but are expensive and have slower response time.
Input lag, because the LCD"s A/D converter waits for each frame to be completely been output before drawing it to the LCD panel. Many LCD monitors do post-processing before displaying the image in an attempt to compensate for poor color fidelity, which adds an additional lag. Further, a video scaler must be used when displaying non-native resolutions, which adds yet more time lag. Scaling and post processing are usually done in a single chip on modern monitors, but each function that chip performs adds some delay. Some displays have a video gaming mode which disables all or most processing to reduce perceivable input lag.
Loss of brightness and much slower response times in low temperature environments. In sub-zero environments, LCD screens may cease to function without the use of supplemental heating.
The production of LCD screens uses nitrogen trifluoride (NF3) as an etching fluid during the production of the thin-film components. NF3 is a potent greenhouse gas, and its relatively long half-life may make it a potentially harmful contributor to global warming. A report in Geophysical Research Letters suggested that its effects were theoretically much greater than better-known sources of greenhouse gasses like carbon dioxide. As NF3 was not in widespread use at the time, it was not made part of the Kyoto Protocols and has been deemed "the missing greenhouse gas".
Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.
Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.
Explanation of CCFL backlighting details, "Design News — Features — How to Backlight an LCD" Archived January 2, 2014, at the Wayback Machine, Randy Frank, Retrieved January 2013.
LCD Television Power Draw Trends from 2003 to 2015; B. Urban and K. Roth; Fraunhofer USA Center for Sustainable Energy Systems; Final Report to the Consumer Technology Association; May 2017; http://www.cta.tech/cta/media/policyImages/policyPDFs/Fraunhofer-LCD-TV-Power-Draw-Trends-FINAL.pdf Archived August 1, 2017, at the Wayback Machine
K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. 37 (1): 1079–1082. doi:10.1889/1.2433159. S2CID 129569963.
Jack H. Park (January 15, 2015). "Cut and Run: Taiwan-controlled LCD Panel Maker in Danger of Shutdown without Further Investment". www.businesskorea.co.kr. Archived from the original on May 12, 2015. Retrieved April 23, 2015.
NXP Semiconductors (October 21, 2011). "UM10764 Vertical Alignment (VA) displays and NXP LCD drivers" (PDF). Archived from the original (PDF) on March 14, 2014. Retrieved September 4, 2014.
"Samsung to Offer "Zero-PIXEL-DEFECT" Warranty for LCD Monitors". Forbes. December 30, 2004. Archived from the original on August 20, 2007. Retrieved September 3, 2007.
"Display (LCD) replacement for defective pixels – ThinkPad". Lenovo. June 25, 2007. Archived from the original on December 31, 2006. Retrieved July 13, 2007.
Explanation of why pulse width modulated backlighting is used, and its side-effects, "Pulse Width Modulation on LCD monitors", TFT Central. Retrieved June 2012.
An enlightened user requests Dell to improve their LCD backlights, "Request to Dell for higher backlight PWM frequency" Archived December 13, 2012, at the Wayback Machine, Dell Support Community. Retrieved June 2012.
Oleg Artamonov (January 23, 2007). "Contemporary LCD Monitor Parameters: Objective and Subjective Analysis". X-bit labs. Archived from the original on May 16, 2008. Retrieved May 17, 2008.
IPS (in-plane switching) is a screen technology for liquid-crystal displays (LCDs). In IPS, a layer of liquid crystals is sandwiched between two glass surfaces. The liquid crystal molecules are aligned parallel to those surfaces in predetermined directions (in-plane). The molecules are reoriented by an applied electric field, whilst remaining essentially parallel to the surfaces to produce an image. It was designed to solve the strong viewing angle dependence and low-quality color reproduction of the twisted nematic field effect (TN) matrix LCDs prevalent in the late 1980s.
The TN method was the only viable technology for active matrix TFT LCDs in the late 1980s and early 1990s. Early panels showed grayscale inversion from up to down,Vertical Alignment (VA)—that could resolve these weaknesses and were applied to large computer monitor panels.
Shortly thereafter, Hitachi of Japan filed patents to improve this technology. A leader in this field was Katsumi Kondo, who worked at the Hitachi Research Center.thin-film transistor array as a matrix and to avoid undesirable stray fields in between pixels.Super IPS). NEC and Hitachi became early manufacturers of active-matrix addressed LCDs based on the IPS technology. This is a milestone for implementing large-screen LCDs having acceptable visual performance for flat-panel computer monitors and television screens. In 1996, Samsung developed the optical patterning technique that enables multi-domain LCD. Multi-domain and in-plane switching subsequently remain the dominant LCD designs through 2006.
IPS technology is widely used in panels for TVs, tablet computers, and smartphones. In particular, most IBM products was marketed as CCFL backlighting, and all Apple Inc. products marketed with the label backlighting since 2010.
Most panels also support true 8-bit-per-channel colour. These improvements came at the cost of a lower response time, initially about 50 ms. IPS panels were also extremely expensive.
In this case, both linear polarizing filters P and A have their axes of transmission in the same direction. To obtain the 90 degree twisted nematic structure of the LC layer between the two glass plates without an applied electric field (OFF state), the inner surfaces of the glass plates are treated to align the bordering LC molecules at a right angle. This molecular structure is practically the same as in TN LCDs. However, the arrangement of the electrodes e1 and e2 is different. Because they are in the same plane and on a single glass plate, they generate an electric field essentially parallel to this plate. The diagram is not to scale: the LC layer is only a few micrometers thick and so is very small compared with the distance between the electrodes.
The LC molecules have a positive dielectric anisotropy and align themselves with their long axis parallel to an applied electrical field. In the OFF state (shown on the left), entering light L1 becomes linearly polarized by polarizer P. The twisted nematic LC layer rotates the polarization axis of the passing light by 90 degrees, so that ideally no light passes through polarizer A. In the ON state, a sufficient voltage is applied between electrodes and a corresponding electrical field E is generated that realigns the LC molecules as shown on the right of the diagram. Here, light L2 can pass through polarizer A.
Unlike TN LCDs, IPS panels do not lighten or show tailing when touched. This is important for touch-screen devices, such as smartphones and tablet computers.
Toward the end of 2010 Samsung Electronics introduced Super PLS (Plane-to-Line Switching) with the intent of providing an alternative to the popular IPS technology which is primarily manufactured by LG Display. It is an "IPS-type" panel technology, and is very similar in performance features, specs and characteristics to LG Display"s offering. Samsung adopted PLS panels instead of AMOLED panels, because in the past AMOLED panels had difficulties in realizing full HD resolution on mobile devices. PLS technology was Samsung"s wide-viewing angle LCD technology, similar to LG Display"s IPS technology.
In 2012 AU Optronics began investment in their own IPS-type technology, dubbed AHVA. This should not be confused with their long standing AMVA technology (which is a VA-type technology). Performance and specs remained very similar to LG Display"s IPS and Samsung"s PLS offerings. The first 144 Hz compatible IPS-type panels were produced in late 2014 (used first in early 2015) by AUO, beating Samsung and LG Display to providing high refresh rate IPS-type panels.
Baker, Simon (30 April 2011). "Panel Technologies: TN Film, MVA, PVA and IPS Explained". Tftcentral.co.uk. Archived from the original on 29 June 2017. Retrieved 13 January 2012.
Many TVs use LCD (Liquid Crystal Display) panels that are lit by LED backlights. There are two popular types of LCD panels: In-Plane Switching (IPS) and Vertical Alignment (VA), and there are two main differences between each type. A VA panel usually has a high contrast ratio and narrow viewing angles. However, an IPS panel has low contrast and wide viewing angles. These are the main differences between each, and for the most part, panel type doesn"t affect other aspects of picture quality, like peak brightness, color gamut, or color accuracy.
For the purposes of this article, we"re going to compare two LED-backlit LCD TVs: the Sony X800H, which has an IPS panel, and the Hisense H9G, which has a VA panel. Due to their different panel types, there are three noticeable differences in picture quality: viewing angles, contrast, and black uniformity, so we"re going to look at each one.
Viewing angle refers to the angle at which you can watch the TV without seeing a noticeable drop in picture quality. IPS TVs are the clear winner here, as the image remains accurate when viewing from the side - you can see the differences in the videos above. This is their main advantage over VA panels. Most VA panel TVs have a noticeable loss in image accuracy when viewing from the side. The narrow viewing angle of VA-type TVs is also problematic when the TV is used as a PC monitor from up close since the edges of the display look washed out.
VA panels are far superior to IPS panels when it comes to this, so if you tend to watch movies in the dark, you likely want to get a TV with a VA panel. Most TVs use VA panels due to this main advantage, and high-end models may have a local dimming feature that further enhances black levels. On the other hand, IPS panels normally have low contrast, so blacks look closer to gray, but you may not notice the difference in contrast in bright environments.
Our black uniformity tests determine how well a TV displays a dark scene with a bright image in the center. Ideally, you want to see a completely black screen with the center cross being the only part that"s lit up, and this is important for people watching movies. No LED TV has perfect uniformity, and unlike viewing angles and contrast, the panel type doesn"t completely determine its black uniformity. However, most VA panels that we"ve tested have good black uniformity, while most IPS panels have sub-par black uniformity. This doesn"t mean that every VA panel TV has good uniformity, as this can change between units, and you can also improve uniformity using the local dimming feature.
LCDs function by having liquid crystals in little groups to form the pixels. These crystals react and change position when charged with electricity and, depending on their position, they allow a certain color of light to pass through.
There"s also another type of IPS panel, called Plane-to-Line Switching (PLS), which can be seen with the Sony X800H. This panel type was designed by Samsung and technically performs the same as an IPS panel. When you compare the pixels visually, IPS panels look like chevrons, VA looks like very straight rectangles, and PLS looks like round-edged capsules. You can learn more about pixels here.
The way the pixels are laid out can also affect text clarity. Many IPS panels, like the ones on the Sony X800H or the LG SK9000, use RGB sub-pixel layouts, while many VA panels have a BGR layout, like on the Hisense H9G. The sub-pixel layout doesn"t directly affect picture quality unless you"re using it as a PC monitor. Some applications may expect an RGB layout, so if you have a BGR sub-pixel layout, text may not look clear. You may need to increase the text scaling to read it properly, but this issue isn"t common with an RGB layout. You can learn more about it here.
Unlike LED TVs, OLEDs don"t use a backlight and instead have self-emitting pixels. This allows the pixels to individually turn on and off, resulting in perfect blacks. This means that they also have perfect black uniformity as there"s no blooming around bright objects like on some LED TVs. They also have wide viewing angles, sometimes even wider than some IPS panels, so OLEDs are a good choice for wide seating arrangements.
Samsung released quantum dot TVs in 2015, which they later labeled as QLED in 2017. These TVs include a quantum dot layer between the LED backlights and the LCD panel to achieve a wider color gamut. Other companies like Vizio and TCL also use this quantum dot technology on their TVs. Adding this extra quantum dot layer doesn"t change the characteristics of the panel type; the VA panel on the TCL 6 Series/S635 2020 QLED still has a high contrast ratio and narrow viewing angles. Although most QLED TVs use VA panels, you can easily use an IPS panel as well.
Manufacturers have tried different techniques to improve the viewing angles on VA panels over the years, aiming to produce a perfect LCD panel with both wide viewing angles and high contrast. While they have yet to achieve that goal, a few TVs have hit the market that try to combine the best of both panel types. The first TVs with this viewing angle technology came out in 2018, and only a few high-end models like the Samsung Q90/Q90T QLED and the Sony X950H had this technology in 2020. These TVs are a bit unique, delivering noticeably better viewing angles than their pure VA counterparts, but still worse than true IPS panels. This comes at the expense of a lower contrast ratio, as these TVs have worse native contrast than most VA panels, but they"re still better than IPS panels. Combined with their local dimming features, they still produce deep blacks.
Between IPS and VA panels, neither technology is inherently superior to the other as they both serve different purposes. In general, IPS TVs have wide viewing angles suitable for when you want to watch the big game or your favorite show in a large seating arrangement. They"re also beneficia