1st row lcd monitors 3 made in china
BEIJING (Reuters) - Two new Chinese LCD screens in Beijing’s imposing Great Hall of the People will replace screens made by a Japanese competitor, in a sign of resolve to supply the world with Chinese brands and not just Made in China products.Delegates arrive for the National People"s Congress (NPC), China"s annual parliament, in the Great Hall of the People in Beijing March 9, 2012. REUTERS/David Gray
The screens are made by Chinese electronics giant TCL. At 110 inches, they are the world’s largest high-definition 3-D LCD screens, just a touch wider than the 108-inch Panasonic models they will replace.
The surging demand for intelligent and connected vehicles, in-vehicle infotainment systems and navigation systems among others gives a big boost to the automotive display market. The statistics from our automotive database show that in 2020 China shipped more than 35 million sets of passenger car displays (cluster, center console, entertainment display, HUD, etc.), up over 4% more than in the previous year.
Automotive display is a key booster to the digital transformation of automotive cockpits. The better performance of on-board computers enables the central computing unit to support LCD cluster, high-resolution infotainment display, HUD, electronic rearview mirror and other display systems, and provides technical support for multi-display systems.
From the new models launched in recent two years, it can be seen that large-size display and multi-screen display have been trends for automotive displays. High-end models have begun to pack at least 4 displays. Products like co-pilot seat entertainment display, control display, rear row entertainment display and streaming media rearview mirror have started finding application, and the demand for large-size displays has been soaring.
The installation of clusters shows that about 60% of new vehicles carry LCD clusters. In the first three quarters of 2021, 6.544 million LCD clusters were installed in passenger cars, a like-on-like spurt of 44.5%, of which 12.0-inch (incl.) to 13.0-inch (excl.) LCD clusters were most installed, up to 2.512 million units, up by 35.0%, and 10.0-inch (incl.) to 12.0-inch (excl.) LCD clusters grew at the fastest pace with the installations rocketing by 173.8% to 1.186 million units.
From center console displays, it can be seen that the installations of large-size ones have surged. In the first three quarters of 2021, 8.0-inch to 9.0-inch center console displays were most installed, up to 4.016 million units, up by 4.3% from the prior-year period, but with the proportion of the total center console display installations down 4.2 percentage points; the installations of 13.0-inch to 15.0-inch center console displays proliferated by 250.6%; that of 15.0-inch and above center console displays multiplied by 204.0%.
FAW Hongqi H9 unveiled in August 2020 bears dashboard, center console, and co-pilot seat entertainment displays, 2 rear row entertainment displays, and HUD. In addition, it also packs an electronic image acquisition and display system (i.e., streaming media rearview mirror) which consists of digital camera, image processing and high-definition digital display. The system uses the rear camera to project images onto the display, and displays them on the rearview mirror in digital format.
Great Wall Mecha Dragon introduced in November 2021 is equipped with 10.25-inch dashboard, 27-inch 4K center console display, 25-inch head-up display, two 1.6-inch touch bars, and two rear row capacitive touch screens, as well as external display technology at the rear.
The soaring demand for vehicle displays give impetus to development of new vehicle display technologies. In current stage, a-Si TFT LCD still prevail in vehicle display market, but advanced display technologies such as LTPS TFT LCD, OLED, mini LED backlight and micro LED are making their way into the market.
2021 Mercedes-Benz S-Class sedans differ greatly from the previous generations in application of displays, changing the original siamesed center console display into a large waterfall display, a 12.8-inch vertical waterfall OLED screen with resolution of 1888×1728. They also pack a glasses-free 3D full LCD dashboard, HUD and rear row entertainment display, which connect with each other.
Mini LED is a necessary transition phase from fine pitch LED to Micro LED. At present, most vehicle display technology companies have deployed Mini LED and Micro LED, and ever more vehicle projects use mini LED backlight technology. One example is Cadillac Lyriq EV in which GM plans to use a 33-inch mini LED backlit display in 2022.
Automotive displays head in the direction of large size and multi-screen integration, and the surging demand creates huge room to grow. Various suppliers are therefore trying hard to deploy innovative technologies such as Mini LED and Micro LED.
Tianma Microelectronics works to deploy Mini LED and Micro LED technologies. Following the on-site exhibition of its self-developed LTPS AM Mini LED HDR display at annual meeting of Society for Information Display (SID) early in 2019, the company showcased its Micro LED technologies online at SID 2021, including 5.04" Splitting ultra-narrow bezel Micro LED, the world’s first 7.56" transparent Micro LED, and innovative technology applications combined with electronic paper.
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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.
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.
Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. This means that a 4K TV cannot display the full UHD TV standard. The media and internet users later called this "RGBW" TVs because of the white sub pixel. Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it became more popular in the TV market because the announced 4K UHD resolution but still being incapable of achieving true UHD resolution defined by the CTA as 3840x2160 active pixels with 8-bit color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.
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.
Uneven backlighting in some monitors (more common in IPS-types and older TNs), causing brightness distortion, especially toward the edges ("backlight bleed").
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.
Several different families of liquid crystals are used in liquid crystal displays. The molecules used have to be anisotropic, and to exhibit mutual attraction. Polarizable rod-shaped molecules (biphenyls, terphenyls, etc.) are common. A common form is a pair of aromatic benzene rings, with a nonpolar moiety (pentyl, heptyl, octyl, or alkyl oxy group) on one end and polar (nitrile, halogen) on the other. Sometimes the benzene rings are separated with an acetylene group, ethylene, CH=N, CH=NO, N=N, N=NO, or ester group. In practice, eutectic mixtures of several chemicals are used, to achieve wider temperature operating range (−10..+60 °C for low-end and −20..+100 °C for high-performance displays). For example, the E7 mixture is composed of three biphenyls and one terphenyl: 39 wt.% of 4"-pentyl[1,1"-biphenyl]-4-carbonitrile (nematic range 24..35 °C), 36 wt.% of 4"-heptyl[1,1"-biphenyl]-4-carbonitrile (nematic range 30..43 °C), 16 wt.% of 4"-octoxy[1,1"-biphenyl]-4-carbonitrile (nematic range 54..80 °C), and 9 wt.% of 4-pentyl[1,1":4",1-terphenyl]-4-carbonitrile (nematic range 131..240 °C).
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".
Critics of the report point out that it assumes that all of the NF3 produced would be released to the atmosphere. In reality, the vast majority of NF3 is broken down during the cleaning processes; two earlier studies found that only 2 to 3% of the gas escapes destruction after its use.3"s effects with what it replaced, perfluorocarbon, another powerful greenhouse gas, of which anywhere from 30 to 70% escapes to the atmosphere in typical use.
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The company was founded in 1987 as Keypoint Technology Corporation by James Chu and was renamed to its present name in 1993, after a brand name of monitors launched in 1990. Today, ViewSonic specializes in visual display hardware—including liquid-crystal displays, projectors, and interactive whiteboards—as well as digital whiteboarding software. The company trades in three key markets: education, enterprise, and entertainment.
The company was initially founded as Keypoint Technology Corporation in 1987 by James Chu. In 1990 it launched the ViewSonic line of color computer monitors, and shortly afterward the company renamed itself after its monitor brand.
In the mid-1990s, ViewSonic rose to become one of the top-rated makers of computer CRT monitors, alongside Sony, NEC, MAG InnoVision, and Panasonic. ViewSonic soon displaced the rest of these companies to emerge as the largest display manufacturer from America/Japan at the turn of the millennium.
In 2005, ViewSonic and Tatung won a British patent lawsuit filed against them by LG Philips in a dispute over which company created technology for rear mounting of LCDs in a mobile PC (U.K. Patent GB2346464B, titled “portable computer").
In 2000, ViewSonic partnered with AT&T Corporation to offer Internet appliances integrated with the AT&T WorldNet Service, initially targeting the corporate market. The Internet appliances ranged from standalone i-boxes, integrated LCD and CRT devices, to web phones and wireless web pads. The units were deemed capable of operating on nearly any operating system, including Windows CE, Linux, QNX and VxWorks.
At the 2007 Consumer Electronics Show, ViewSonic introduced display products, namely a projector, monitors and an HDTV set, capable of being connected directly to a video iPod.
On May 31, 2011, the ViewPad 7x debuted at the Computex computer show in Taipei, Taiwan, Pocket-Lint reported, being a follow-up rather than a replacement to ViewSonic"s existing ViewPad 7 tablet, which runs Android 2.2, a.k.a. Froyo.
Video memory is typically stored on a video card. Video cards have their own processor called a Graphics Processing Unit (GPU), or a Visual Processing Unit (VPU). These processors use graphics RAM that is installed on the video card to store data so that the RAM on the motherboard is not used. The more RAM that is on the card, the better the performance. Most video cards today use DDR2, DDR3, graphics DDR3 (GDDR3), GDDR4, or GDDR5 memory. The Graphics DDR memory is faster and does a better job than the regular DDR memory. To see how much video memory is available in the windows OS click on the Adjust Screen Resolution tab, then click the advanced settings option.
An LCD with excellent "video" display quality is essential to fully enjoy video content. We have prepared a number of sample videos to check the video display quality of your LCD.
Note: Below is the translation from the Japanese of the ITmedia article "Are the response time figures true!? Let"s check LCD video performance" published May 31, 2010. Copyright 2011 ITmedia Inc. All Rights Reserved.
Have you ever consciously checked your current LCD"s video display capability? First of all, we"d like you to play the video below. It starts with a row of letters moving slowly from right to left but the letters gradually pick up speed and the direction in which they move also changes. Clicking on the title above the video takes you to YouTube where you can change the resolution and play it on the whole screen, so we would like you to set the resolution to suit your environment when you play this clip.
The row of letters probably is displayed fairly sharply at first, but in many cases we expect that the contours of the letters became blurred as they picked up speed and that the display of the letters gradually broke down at high speeds.
We would like you to try the next video now. The row of letters and the speeds at which it moves are exactly the same but the background and the letters are different colors.
If both these videos were displayed smoothly then the video playback performance is good. On the other hand, if both of them had blurring and flickering from the start and could not be displayed satisfactorily, you should perhaps doubt your LCD"s video display capability.
There are a number of points to bear in mind when assessing LCD image quality, but it"s probably best to consider the image quality of still images and video separately, to a certain degree. The performance required to reproduce a still image beautifully on the screen is different from that required to display video clearly on the screen. This time we will focus on video image quality, and on the extended definition technology that boosts video image quality.
The general term video encompasses many different kinds of video, such as SD and HD with their different resolutions, and different genres such as live-action, animation and games. There are also different kinds of output devices such as computers, DVD / Blu-ray Disc players and game consoles.Recently LCDs require extended definition technology compatible with the kind of video or the external device, since the quality of the video source is improving and LCDs need to be connected to devices other than computers.
Anyway, let"s check the settings of the LCD you are using. If your LCD is equipped with video quality modes according to purpose, you should select a video-oriented mode such as "Video" or "Movie" and play a clip of your choice. We would then like you to compare it viewed in the "Standard" and "sRGB" image quality modes. In general, video-oriented image quality modes tend to boost things like brightness and contrast, saturation and color temperature. People have particularly strong personal preferences when it comes to coloration so this may not always be the case, but strong brightness, contrast and saturation boost the video"s appeal and give a sense of high image quality.
To go into a little more detail, video image quality is not determined by the LCD alone. If video is being played on a computer, a low power CPU causes visual and audio jumpiness, as well as which the image quality changes slightly according to the software on which the video is played. Furthermore, just as AMD"s GPU "ATI Radeon" series has "Avivo" and NVIDIA"s GPU "GeForce" series has "PureVideo", the CPU load reduction and the video extended definition technology from the GPU and driver playback support functions have a very strong effect. Also, when the LCD is connected to an AV device or game console, the image quality changes according to video playback function of those devices and the connection interface.
In this article we focus on the video playback performance of LCDs, but we would like you to remember that you also need be choosy about the video output environment if you want higher quality for your video display.
"Response time" is known to be the most easily understandable indicator amongst the LCD specifications influencing video display quality. The response time indicates the speed with which a pixel (dot) on the screen changes from one color to another. Strictly speaking, "speed" is measured in units such as "kilometers per hour" but LCD response time is shown in "ms" (milliseconds).
In many cases two values are given for the response time of an LCD. The first is the black-white-black response time (the crystal rise time + fall time), and is the total time that it takes for one pixel to change from black to white and white to black. As of May 2010, the fastest class of LCDs have achieved high-speed response times of 1 ms or 2 ms.
The other value is the middle gradation response time. It is the time that it takes a pixel to change from gray to gray (from one gradation of gray to another). An LCD has 256 gradations of gray, and in most cases several gradations are selected and the response time measured, and then the average value is taken as the middle gradation response time. LCDs with a fast middle gradation response time boast speeds of around 2 to 5 ms, and this is recorded in the specifications as "Gray-to-gray" or "G to G". Middle gradation colors are far more prevalent in video display colors (there are not many scenes that switch back and forth between black and white) so the middle gradation response time is very important for video image quality.
If we simply consider the figures, LCDs with fast response times have better video display quality. The screen colorations change quickly so fast moving images are displayed clearly and sharply. Slow response times, caused by slow coloration changes, can lead to fuzzy displays (blur) or afterimages being left of the outlines of the objects moving on the screen.
We should also remember response time tendencies according to how the liquid crystal panel used in the LCD is driven. Generally, although it is easy to accelerate the black -white-black response time with TN and VA liquid crystal panels (and particularly with TN ones), the middle gradation response time is easily slowed. Although it is hard to accelerate the response time for the entire gradation range with IPS liquid crystal panels, there is less slowing in the middle gradations than with the other types and they tend to be assessed as having stable display content.
Recently more and more LCDs are installed with technology to improve response times and also to reduce blur. This technology is typified by overdrive circuits, black insertion and accelerator drives, which we will introduce here.
Black insertion is a technique to reduce blur and afterimages. Basically the refresh rate of an LCD is 60 Hz (although there are exceptions to this) so the frame rate is 60 fps. This means that the screen (frame) changes every sixtieth of a second. Inserting a pitch-black screen between the frames depicted reduces the appearance of blur and afterimages. This technique is widely adopted for household LCD televisions and is very effective.
Now that we have explained about response times and techniques to reduce blur, let"s use the sample videos shown at the start of this article to do a detailed check on actual LCDs.
The LCDs we will use for the test are the EIZO FlexScan EV2333W, FlexScan SX2462W and FlexScan EV2303W. We are using three models, one for each type of LCD panel drive system. The SX2462W has IPS, the EV2333W has VA and the EV2303W has TN. The specifications for video display performance are given in the chart below.
At first the video scrolls horizontally from right to left, then vertically from bottom to top, and then diagonally from top-left to bottom-right. The lettering is scrolled five times and then speeds up. At first it takes about 10 seconds to get from one edge of the screen to the other, then around 5 seconds and finally around 3 seconds. You should expect that the contours of the lettering have more apparent afterimages and false colors the faster the scrolling goes.
These sample videos have been created to make it easy to find the faults of response times, so probably in most cases faults are even easier to find in standard video content. In fact, at the present there are no computer LCDs that can display the scrolled lettering perfectly, without any afterimages or flickering. We did find afterimages and flickering in all three of our test models when the speed increased, but there was no particularly noticeable breaking up of the lettering or false coloring of their contours, so it was at a level where it was perfectly possible to watch the video content.
The SX2462W (IPS type) is a monitor that is perhaps better with still images but gave a similar impression to that of the EV2333W (VA type) with its overdrive circuit set at "Normal" and there were no obvious faults. The black-white-black response time of the panel itself is 13 ms, fast for an IPS type, and the built-in overdrive circuit boosted the middle gradation response time to 7 ms, producing a very stable video display.
The EV2303W (TN type) has the fastest black-white-black response time, at 5 ms, and although there was little blurring in the monochrome sample video, afterimages were conspicuous in the color sample video. The middle gradation response time has not been revealed but, since it is not equipped with an overdrive circuit, there is the typical TN type characteristic that some tones are very much slower than the change between black and white. At first glance the TN type seems to have a faster response time but we would like you to remember that the middle gradations, much used in normal video content, are slowed (easily blurred).
We played the monochrome lettering sample video and photographed the slow speed scrolling with a digital camera. From the left: the EV2333W (overdrive setting: high), the SX2462W and the EV2303W. The shutter speed was 1/60 sec.
We played the color lettering sample video and photographed the slow speed scrolling with a digital camera. From the left: the (overdrive setting: high), the SX2462W and the EV2303W. The shutter speed was 1/60 sec.
The difference between the EV2333W overdrive settings. From the left: Off, Normal and High You can see how the blurring changes with the intensity of the overdrive circuit
We would like you to adjust the LCD"s OCD menu as necessary while checking whether there is sufficient brightness and contrast. In most cases there is no problem when the brightness is at maximum, but try turning the brightness down slightly if you are bothered by the black looking washed-out and grayish.
The three models we are using for our checks displayed the typical EIZO insistence on beautiful gradation expression, and the gray scale was properly displayed on all three. The EV2303W has the lowest brightness but the darkness of the screen should not be noticeable unless it is in a very bright environment. Both the SX2462W and EV2333W were perfectly bright.
When it came to contrast, as expected the VA-type EV2333W was excellent; it was well-modulated and the black was nice and tight. The IPS-type SX2462W lived up to its reputation as a high-grade model and the black was well expressed. Compared to the other two models, the EV2303W"s dark areas lacked blackness and seemed slightly washed-out, although this was at a level that would not be noticeable if it were not being compared to such high-grade products.
In particular, the coloration should have a very different appearance when the color temperature is raised or lowered. For your reference, the standard computer color temperature and the international standard for HD image color temperature are both 6,500K, while the color temperature is 9,300K for analog TV images and so on in Japan (NTSC). When the color temperature is low the colors on the screen have a reddish tinge, which becomes bluer as the color temperature rises. It is better if it is adjusted to the optimum color temperature for the video image source, but if the product has image quality modes the color temperature is also switched automatically according to the mode, so perhaps we need not worry too much about that.
There are quite a few LCDs whose color balance can be adjusted for each RGB in the