Qualitative properties are properties that are observed and can generally not be measured with a numerical result, unlike quantitative properties , which have numerical characteristics.
89-543: The Mohs scale ( / m oʊ z / MOHZ ) of mineral hardness is a qualitative ordinal scale , from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by the German geologist and mineralogist Friedrich Mohs , in his book Versuch einer Elementar-Methode zur naturhistorischen Bestimmung und Erkennung der Fossilien (English: Attempt at an elementary method for
178-454: 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
267-540: A sclerometer , with images of the reference minerals in the rightmost column. Below is a table of more materials by Mohs scale. Some of them have a hardness between two of the Mohs scale reference minerals. Some solid substances that are not minerals have been assigned a hardness on the Mohs scale. However, hardness can make it difficult to determine if the substance is a mixture of other substances or if it may be misleading or meaningless. For example, some sources have assigned
356-631: A 14-inch, active-matrix, full-color, full-motion TFT-LCD. This led to Japan launching an LCD industry, which developed large-size LCDs, including TFT computer monitors and LCD televisions. Epson developed the 3LCD projection technology in the 1980s, and licensed it for use in projectors in 1988. Epson's VPJ-700, released in January 1989, was the world's first 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
445-493: A Gen 8.5 mother glass, significantly reducing waste. The thickness of the mother glass also increases with each generation, so larger mother glass sizes are better suited for larger displays. An LCD module (LCM) is a ready-to-use LCD with a backlight. Thus, a factory that makes LCD modules does not necessarily make LCDs, it may only assemble them into the modules. LCD glass substrates are made by companies such as AGC Inc. , Corning Inc. , and Nippon Electric Glass . The origin and
534-506: A Mohs hardness of 6 or 7 to granite but it is a rock made of several minerals, each with its own Mohs hardness (e.g. topaz-rich granite contains: topaz — Mohs 8, quartz — Mohs 7, orthoclase — Mohs 6, plagioclase — Mohs 6–6.5, mica — Mohs 2–4). Despite its lack of precision, the Mohs scale is relevant for field geologists, who use it to roughly identify minerals using scratch kits. The Mohs scale hardness of minerals can be commonly found in reference sheets. Mohs hardness
623-572: 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
712-455: A blue polarizer, or birefringence which gives them their distinctive appearance. 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 passive-matrix addressed , because the pixel must retain its state between refreshes without
801-446: A categorical result or a binary classification (e.g., pass/fail, go/no go , conform /non-conform). It can sometimes be an engineering judgement. The data that all share a qualitative property form a nominal category . A variable which codes for the presence or absence of such a property is called a binary categorical variable , or equivalently a dummy variable . Liquid-crystal display A liquid-crystal display ( LCD )
890-419: 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
979-414: A digital clock) are all 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 has black lettering on a background that
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#17327752722251068-646: A few used plasma displays ) and the original Nintendo Game Boy until the mid-1990s, when color active-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
1157-460: 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. After the black resist has been dried in an oven and exposed to UV light through
1246-415: A glass substrate to form the cell circuitry to operate the panel. It is usually not possible to use soldering techniques to directly connect the panel to a separate copper-etched circuit board. Instead, interfacing is accomplished using anisotropic conductive film or, for lower densities, elastomeric connectors . Monochrome and later color passive-matrix LCDs were standard in most early laptops (although
1335-514: 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
1424-412: 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
1513-449: 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
1602-624: A leading position in the wristwatch market, like Seiko 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. A particular type of such a color LCD was developed by Japan's Sharp Corporation in the 1970s, receiving patents for their inventions, such as a patent by Shinji Kato and Takaaki Miyazaki in May 1975, and then improved by Fumiaki Funada and Masataka Matsuura in December 1975. TFT LCDs similar to
1691-426: A material for the purposes of the Mohs scale means creating non- elastic dislocations visible to the naked eye. Frequently, materials that are lower on the Mohs scale can create microscopic, non-elastic dislocations on materials that have a higher Mohs number. While these microscopic dislocations are permanent and sometimes detrimental to the harder material's structural integrity, they are not considered "scratches" for
1780-468: 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
1869-409: A mini-LED backlight and quantum dot sheets. LCDs with quantum dot enhancement film or quantum dot color filters were introduced from 2015 to 2018. Quantum dots receive blue light from a backlight and convert it to light that allows LCD panels to offer better color reproduction. Quantum dot color filters are manufactured using photoresists containing quantum dots instead of colored pigments, and
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#17327752722251958-445: A numerical result. They are contrasted to quantitative properties which have numerical characteristics. Although measuring something in qualitative terms is difficult, most people can (and will) make a judgement about a behaviour on the basis of how they feel treated. This indicates that qualitative properties are closely related to emotional impressions. A test method can result in qualitative data about something. This can be
2047-473: A photomask, the unexposed areas are washed away, creating a black grid. Then the same process is repeated with the remaining resists. This fills the holes in the black grid with their corresponding colored resists. Black matrices made in the 1980s and 1990s when most color LCD production was for laptop computers, are made of Chromium due to its high opacity, but due to environmental concerns, manufacturers shifted to black colored photoresist with carbon pigment as
2136-449: 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
2225-464: A reflective display. The common implementations of LCD backlight technology are: 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
2314-526: A sharper threshold of the contrast-vs-voltage characteristic than the original TN LCDs. This is important, because pixels are subjected to partial voltages even while not selected. Crosstalk between activated and non-activated pixels has to be handled properly by keeping the RMS voltage of non-activated pixels below the threshold voltage as discovered by Peter J. Wild in 1972, while activated pixels are subjected to voltages above threshold (the voltages according to
2403-483: A significant role in this growth, including as a result of their investments in LCD manufacturers via state-owned investment companies. China had previously imported significant amounts of LCDs, and the growth of its LCD industry decreased prices for other consumer products that use LCDs and led to growth in other sectors like mobile phones. LCDs do not produce light on their own, so they require external light to produce
2492-401: 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
2581-641: 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. LCD panels typically use thinly-coated metallic conductive pathways on
2670-531: A video speed-drive scheme that solved the slow response time of STN-LCDs, enabling high-resolution, high-quality, and smooth-moving video images on STN-LCDs. In 1985, Philips inventors Theodorus Welzen and Adrianus de Vaan solved the problem of driving high-resolution STN-LCDs using low-voltage (CMOS-based) drive electronics, allowing the application of high-quality (high resolution and video speed) LCD panels in battery-operated portable products like notebook computers and mobile phones. In 1985, Philips acquired 100% of
2759-416: A visible image. In a transmissive type of LCD, the light source is provided at the back of the glass stack and is called a backlight . Active-matrix LCDs are almost always backlit. Passive LCDs may be backlit but many are reflective as they use a reflective surface or film at the back of the glass stack to utilize ambient light. Transflective LCDs combine the features of a backlit transmissive display and
Mohs scale - Misplaced Pages Continue
2848-496: A voltage to a DSM display switches the initially clear transparent liquid crystal layer into a milky turbid state. DSM displays could be operated in transmissive and in reflective mode but they required a considerable current to flow for their operation. George H. Heilmeier was inducted in the National Inventors Hall of Fame and credited with the invention of LCDs. Heilmeier's work is an IEEE Milestone . In
2937-554: Is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liquid crystals do not emit light directly but instead use a backlight or reflector to produce images in color or monochrome . LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images with low information content, which can be displayed or hidden: preset words, digits, and seven-segment displays (as in
3026-663: 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. In contrast, full alphanumeric or variable graphics displays are usually implemented with pixels arranged as
3115-407: 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
3204-422: 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
3293-475: Is based on an electro-hydrodynamic instability forming what are now called "Williams domains" inside the liquid crystal. Building on early MOSFETs , Paul K. Weimer at RCA developed the thin-film transistor (TFT) in 1962. It was a type of MOSFET distinct from the standard bulk MOSFET. In 1964, George H. Heilmeier , who was working at the RCA laboratories on the effect discovered by Richard Williams, achieved
3382-463: Is needed. Displays having a passive-matrix structure use super-twisted nematic STN (invented by Brown Boveri Research Center, Baden, Switzerland, in 1983; scientific details were published ) or double-layer STN (DSTN) technology (the latter of which addresses a color-shifting problem with the former), and color-STN (CSTN), in which color is added by using an internal color filter. STN LCDs have been optimized for passive-matrix addressing. They exhibit
3471-845: Is the color of the backlight, and a character negative LCD has a black background with the letters being of the same color as the backlight. 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. LCDs are not subject to screen burn-in like on CRTs. However, LCDs are still susceptible to image persistence . Each pixel of an LCD typically consists of
3560-465: 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
3649-443: Is useful for identification of minerals in the field , but is not an accurate predictor of how well materials endure in an industrial setting. The Mohs scale of mineral hardness is based on the ability of one natural sample of mineral to visibly scratch another mineral. Minerals are chemically pure solids found in nature. Rocks are mixtures of one or more minerals. Diamond was the hardest known naturally occurring mineral when
Mohs scale - Misplaced Pages Continue
3738-577: Is useful in milling . It allows the assessment of which type of mill and grinding medium will best reduce a given product whose hardness is known. Electronic manufacturers use the scale for testing the resilience of flat panel display components (such as cover glass for LCDs or encapsulation for OLEDs ), as well as to evaluate the hardness of touch screens in consumer electronics. Comparison between Mohs hardness and Vickers hardness : Qualitative property Qualitative properties are properties that are observed and can generally not be measured with
3827-423: Is written to the display, the display may be cut from the power while retaining readable images. This has the advantage that such ebooks may be operated for long periods of time powered by only a small battery. 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
3916-527: The super-twisted nematic (STN) structure for 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, U.S. patent 4,634,229 and many more countries. In 1980, Brown Boveri started a 50/50 joint venture with
4005-546: The Engineering and Technology History Wiki . 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. In 1904, 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
4094-710: The Wayback Machine ) with Wolfgang Helfrich and Martin Schadt (then working for the Central Research Laboratories) listed as inventors. Hoffmann-La Roche licensed the invention to Swiss manufacturer 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
4183-502: The "Alt & Pleshko" drive scheme). Driving such STN displays according to the Alt & Pleshko drive scheme require very high line addressing voltages. Welzen and de Vaan invented an alternative drive scheme (a non "Alt & Pleshko" drive scheme) requiring much lower voltages, such that the STN display could be driven using low voltage CMOS technologies. White-on-blue LCDs are STN and can use
4272-485: The CRT-based sets, leading to a worldwide energy saving of 600 TWh (2017), equal to 10% of the electricity consumption of all households worldwide or equal to 2 times the energy production of all solar cells in the world. 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
4361-463: The Dutch Philips company, called Videlec. Philips had the required know-how to design and build integrated circuits for the control of large LCD panels. In addition, Philips had better access to markets for electronic components and intended to use LCDs in new product generations of hi-fi, video equipment and telephones. In 1984, Philips researchers Theodorus Welzen and Adrianus de Vaan invented
4450-409: 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
4539-539: The LCD industry. These six companies were fined 1.3 billion dollars by the United States, 650 million Euro by the European Union, and 350 million RMB by China's National Development and Reform Commission . In 2007 the image quality of LCD televisions surpassed the image quality of cathode-ray-tube-based (CRT) TVs. In the fourth quarter of 2007, LCD televisions surpassed CRT TVs in worldwide sales for
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#17327752722254628-753: The Videlec AG company based in Switzerland. Afterwards, Philips moved the Videlec production lines to the Netherlands. Years later, Philips successfully produced and marketed complete modules (consisting of the LCD screen, microphone, speakers etc.) in high-volume production for the booming mobile phone industry. 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. In 1982, Seiko Epson released
4717-401: The addressing method of these bistable displays is rather complex, a reason why these displays did not make it to the market. That changed when in the 2010 "zero-power" (bistable) LCDs became available. Potentially, passive-matrix addressing can be used with devices if their write/erase characteristics are suitable, which was the case for ebooks which need to show still pictures only. After a page
4806-407: 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
4895-410: 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
4984-622: The benefit of a steady electrical charge. As the number of pixels (and, correspondingly, columns and rows) increases, this type of display becomes less feasible. Slow 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. Citizen, among others, licensed these patents and successfully introduced several STN based LCD pocket televisions on
5073-408: The black matrix material. Another color-generation method used in early color PDAs and some calculators was done by varying the voltage in a Super-twisted nematic LCD, where the variable twist between tighter-spaced plates causes a varying double refraction birefringence , thus changing the hue. They were typically restricted to 3 colors per pixel: orange, green, and blue. The optical effect of
5162-703: The complex history of liquid-crystal displays from the perspective of an insider during the early days were described by Joseph A. Castellano in Liquid Gold: The Story of Liquid Crystal Displays and the Creation of an Industry . Another report on the origins and history of LCD from a different perspective until 1991 has been published by Hiroshi Kawamoto, available at the IEEE History Center. A description of Swiss contributions to LCD developments, written by Peter J. Wild , can be found at
5251-404: The determination of a Mohs scale number. Each of the ten hardness values in the Mohs scale is represented by a reference mineral , most of which are widespread in rocks. The Mohs scale is an ordinal scale . For example, corundum (9) is twice as hard as topaz (8), but diamond (10) is four times as hard as corundum. The table below shows the comparison with the absolute hardness measured by
5340-457: The dominant LCD designs through 2006. In the late 1990s, the LCD industry began shifting away from Japan, towards South Korea and Taiwan , and later on towards China. In this period, Taiwanese, Japanese, and Korean manufacturers were the dominant firms in LCD manufacturing. From 2001 to 2006, Samsung and five other major companies held 53 meetings in Taiwan and South Korea to fix prices in
5429-412: The driving circuitry from the borders of the display to in between the pixels, allowing for narrow bezels. 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
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#17327752722255518-413: 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
5607-596: The first LCD television, the Epson TV Watch, a wristwatch equipped with a small active-matrix LCD television. Sharp Corporation introduced dot matrix TN-LCD in 1983. In 1984, Epson released the ET-10, the first full-color, pocket LCD television. The same year, Citizen Watch , introduced the Citizen Pocket TV, a 2.7-inch color LCD TV, with the first commercial TFT LCD . In 1988, Sharp demonstrated
5696-459: 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. In 1971, the company of Fergason, ILIXCO (now LXD Incorporated ), produced LCDs based on the TN-effect, which soon superseded
5785-511: The first flat 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 1973 and then mass-produced TN LCDs for watches in 1975. Other Japanese companies soon took
5874-413: The first major English language publication Molecular Structure and Properties of Liquid Crystals was published by Dr. George W. Gray . In 1962, Richard Williams of 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
5963-409: The first polarizer of the LCD (invented by Philips researchers Adrianus de Vaan and Paulus Schaareman), generally achieved using so called DBEF films manufactured and supplied by 3M. Improved versions of the prism sheet have a wavy rather than a prismatic structure, and introduce waves laterally into the structure of the sheet while also varying the height of the waves, directing even more light towards
6052-476: The first time. LCD TVs were projected to account 50% of the 200 million TVs to be shipped globally in 2006, according to Displaybank . In October 2011, Toshiba announced 2560 × 1600 pixels on a 6.1-inch (155 mm) LCD panel, suitable for use in a tablet computer , especially for Chinese character display. The 2010s also saw the wide adoption of TGP (Tracking Gate-line in Pixel), which moves
6141-478: The inventors worked, assigns these patents to Merck KGaA, Darmstadt, a supplier of LC substances. In 1992, shortly thereafter, engineers at 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. The first wall-mountable LCD TV was introduced by Sharp Corporation in 1992. Hitachi also improved
6230-587: 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)
6319-705: The light of the backlight uniformly, while a mirror is placed behind the light guide plate to direct all light forwards. The prism sheet with its diffuser sheets are placed on top of the light guide plate. The DBEF polarizers consist of a large stack of uniaxial oriented birefringent films that reflect the former absorbed polarization mode of the light. DBEF polarizers using uniaxial oriented polymerized liquid crystals (birefringent polymers or birefringent glue) were invented in 1989 by Philips researchers Dirk Broer, Adrianus de Vaan and Joerg Brambring. The combination of such reflective polarizers, and LED dynamic backlight control make today's LCD televisions far more efficient than
6408-451: 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. An example is a mixture of 2-(4-alkoxyphenyl)-5-alkylpyrimidine with cyanobiphenyl, patented by Merck and Sharp Corporation . The patent that covered that specific mixture has expired. Most color LCD systems use
6497-468: The market. 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. Since a pixel may be either in an on-state or in an off state at the moment new information needs to be written to that particular pixel,
6586-520: The natural-historical determination and recognition of fossils); it is one of several definitions of hardness in materials science , some of which are more quantitative. The method of comparing hardness by observing which minerals can scratch others is of great antiquity, having been mentioned by Theophrastus in his treatise On Stones , c. 300 BC , followed by Pliny the Elder in his Naturalis Historia , c. AD 77 . The Mohs scale
6675-476: 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 first wristwatch with TN-LCD was launched on the market: The Gruen Teletime which was a four digit display watch. In 1972, the concept of the active-matrix thin-film transistor (TFT) liquid-crystal display panel
6764-561: 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, then improved in 1977 by a Sharp team consisting of Kohei Kishi, Hirosaku Nonomura, Keiichiro Shimizu, and Tomio Wada. However, these TFT-LCDs were not yet ready for use in products, as problems with the materials for the TFTs were not yet solved. In 1983, researchers at Brown, Boveri & Cie (BBC) Research Center, Switzerland , invented
6853-456: The quantum dots can have a special structure to improve their application onto the color filter. Quantum dot color filters offer superior light transmission over quantum dot enhancement films. In the 2020s, China became the largest manufacturer of LCDs and Chinese firms had a 40% share of the global market. Chinese firms that developed into world industry leaders included BOE Technology , TCL-CSOT, TIANMA, and Visionox. Local governments had
6942-535: The response time is reduced to just 5 milliseconds when compared with normal STN LCD panels which have a response time of 16 milliseconds. FSC LCDs contain a Chip-On-Glass driver IC can also be used with a capacitive touchscreen. This technique can also be applied in displays meant to show images, as it can offer higher light transmission and thus potential for reduced power consumption in the backlight due to omission of color filters in LCDs. Samsung introduced UFB (Ultra Fine & Bright) displays back in 2002, utilized
7031-508: 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 thin-film transistor (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 colored photoresists (resists) are used to create color filters. All resists contain
7120-431: The scale was designed, and defines the top of the scale, arbitrarily set at 10. The hardness of a material is measured against the scale by finding the hardest material that the given material can scratch, or the softest material that can scratch the given material. For example, if some material is scratched by apatite but not by fluorite , its hardness on the Mohs scale would be between 4 and 5. Technically, "scratching"
7209-413: The screen and reducing aliasing or moiré between the structure of the prism sheet and the subpixels of the LCD. A wavy structure is easier to mass-produce than a prismatic one using conventional diamond machine tools, which are used to make the rollers used to imprint the wavy structure into plastic sheets, thus producing prism sheets. A diffuser sheet is placed on both sides of the prism sheet to distribute
7298-574: 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,
7387-524: 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
7476-400: The switching of colors by field-induced realignment of dichroic dyes in a homeotropically oriented liquid crystal. Practical problems with this new electro-optical effect made Heilmeier continue to work on scattering effects in liquid crystals and finally the achievement of the first operational liquid-crystal display based on what he called the dynamic scattering mode (DSM). Application of
7565-625: 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
7654-499: 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
7743-441: Was conceived by Bernard Lechner of RCA Laboratories in 1968. Lechner, F.J. Marlowe, E.O. Nester and J. Tults demonstrated the concept in 1968 with an 18x2 matrix 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 Archived March 9, 2021, at
7832-510: Was prototyped in the United States by T. Peter Brody 's team at Westinghouse , in Pittsburgh, Pennsylvania . In 1973, Brody, J. A. Asars and G. D. Dixon at Westinghouse Research Laboratories demonstrated the first thin-film-transistor liquid-crystal display (TFT LCD). As of 2013 , all modern high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays. Brody and Fang-Chen Luo demonstrated
7921-557: Was to use interdigital electrodes on one glass substrate only to produce an electric field essentially parallel to the glass substrates. To take full advantage of the properties of this In Plane Switching (IPS) technology further work was needed. After thorough analysis, details of advantageous embodiments are filed in Germany by Guenter Baur et al. and patented in various countries. The Fraunhofer Institute ISE in Freiburg, where
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