lcd screen blotches factory

• Perform highly diversified duties to install and maintain electrical apparatus on production machines and any other facility equipment (Screen Print, Punch Press, Steel Rule Die, Automated Machines, Turret, Laser Cutting Machines, etc.).

I got this strange ‘dust problem’ on my Mac. In December 2009 my dream came true and I purchased new lovely Apple iMac 27”, 2.66, i5. One day I have noticed dark grey smudges on both sides of the screen (left and right). I actually didn"t notice any spots until I changed the background to pure white (or any other solid color really). At first, I thought it was fingerprint smudges or something. I cleaned the entire screen and it still remains.

I contacted with Apple service and they said iMac is very sensitive to dust. They call it ‘interlaminar dust’in matrix. As time passes, dust accumulates inside the machine and irreversibly penetrates the LCD itself, causing the dark stains. They blamed environment in my room! My Mac is placed on a normal work desk with lots of space around it and not more dust then in a normal house. Not that I am surprised that iMac is very sensitive to dust but I am so woefully disappointed.

Most people believe it was a factory defect on the LCDs. The only trouble they say is how to convince Apple Service to make a replacement of LCD under Apple repair program. They say if you pushy enough might get lucky and Apple might fix it for you.

Accidental Damage is any damage due to an unintentional act that is not the direct result of a manufacturing defect or failure. Accidental damage is not covered under the standard warranty of the product. Such damage is often the result of a drop or an impact on the LCD screen or any other part of the product which may render the device non-functional. Such types of damage are only covered under an Accidental Damage service offering which is an optional add-on to the basic warranty of the product. Accidental Damage must not be confused with an occasional dead or stuck pixel on the LCD panel. For more information about dead or stuck pixels, see the Dell Display Pixel Guidelines.

The LCD glass on the display is manufactured to rigorous specifications and standards and will not typically crack or break on its own under normal use. In general, cracked, or broken glass is considered accidental damage and is not covered under the standard warranty.

Internal cracks typically occur due to excessive force on the screen. This can be the result of some object hitting the screen, a drop, attempting to close the lid while an object is on the keypad area, or even holding the laptop by its screen.

Spots typically occur due to an external force hitting the screen causing damage to the LCD panel"s backlight assembly. While the top layer did not crack or break, the underlying area was compressed and damaged causing this effect.

If your Dell laptop LCD panel has any accidental damage but the laptop is not covered by the Accidental Damage service offering, contact Dell Technical Support for repair options.

Is your obsessive side getting twitchy yet? Before we discuss upping your Xanax prescription, let"s review how the DSE demon begins its possession of your beloved screen.

Still, DSE may afflict cheaper versions, particularly if the anti-reflective coating on the glass that overlays the screen is of low quality or poorly applied. Furthermore, as the display ages, the phosphors in the screen may begin to wear out or malfunction, all of which can contribute to less uniform images, which is often apparent particular in scenes with fast panning shots.

In LCD and LED TVs, DSE is typically a bigger issue, one that"s due to the way these units are illuminated. Before we proceed, it"s worth mentioning that although marketing-speak often treats LED and LCD TVs as completely different technologies, they"re not different beasts.

LED units could be more accurately described as "LED-backlit LCD televisions," but salespeople and consumers alike are too lazy to utter that tongue-wearying phrase while haggling in a big-box store. What"s important to realize is that both categories rely on LCDs (liquid crystal displays), which act as shutters that either block light or allow it to pass, depending on the image that"s being rendered on the screen.

There are a variety of factors that affect LCD quality, notably illumination source. Older LCD TVs, for example, used multiple cold cathode fluorescent lamps (CCFL) to light LCDs from the rear. They provide generally smooth and even illumination, but they make the final product rather bulky.

More modern TVs rely on LEDs (light-emitting diodes) as a light source. Some models have what"s called full-array backlighting, in which the LEDs are stationed in regular intervals behind the screen, creating even lighting and excellent picture quality.

Other models incorporate what"s called edge lighting, which positions the LEDs along the edges of the screen. In general, the overall picture quality isn"t quite as good as a backlit screen, but manufacturers still use it because it allows them to build substantially slimmer TVs.

If you"ve ever pressed a little too hard on your smartphone or computer screen, you"ve likely witnessed a bit of discoloration, clear evidence of how sensitive LCDs are to physical pressure. Now, picture a huge manufacturing facility that cranks out thousands of these units per week. It"s easy to see how a bit of mishandling could alter the screen"s consistency.

The same goes for shipping. Some units travel long distances in cargo boxes, and then take bouncy rides in your car to their final resting place on your living room wall. That"s a lot of opportunities for tiny mishaps to affect LCD uniformity.

With an LCD TV you can watch your favorite movies, cartoons, and series in excellent quality with high definition and good sound. However, owners of LCD monitors may encounter the problem of dark spots appearing on the screen. Let’s take a closer look at the reasons for their appearance and what are the best solutions to repair them.

So What Causes Dark Spots on TV Screen?Dark (black) spots on LCD TVs are typically caused by either debris or superficial dirt, a dead pixel, or a stuck pixel. Of all these problems, the easiest problem to fix is debris or superficial dirt. On the contrary, stuck pixels are harder to fix, while dead pixels are the hardest problem to fix.

It is very often, that dark spots appear on LCD TV screens, including popular brands such as Samsung, Sony, LG, and others. They can be localized in one corner, centered, or in several places at once.

Mechanical damage. An especially common reason is when there are children in the house playing with a ball in the apartment. A strong blow or pressure will stain the CRT. Broken pixels first appear in the affected area, then spread across the screen.

Before trying to disassemble an LCD TV or hand it over to a service center, it is worth excluding software failures that are possible with digital broadcasting. The test scheme for Samsung, Sony, and LG are common. There may be some nuances depending on the TV model.

If the black spots on your LCD TV screen disappear, the cause was most likely a software failure. In such a situation, it is not necessary to disassemble or repair the device in the service. If the malfunction remains, it is better to contact a professional to repair an expensive modern TV.

One of the reasons for the appearance of spots in the external adhesion of dirt, dust. In such a situation, it is not necessary to disassemble the equipment or reboot it. It is enough to wash the screen surface. For this:

In most cases it takes from 1 to 5 working days to repair and remove dark spots on a TV screen, depending on the workload of the wizard and the availability of parts in the service. The cost of repairs depends on the degree of damage and the price of spare parts.

Proper care of household appliances is the key to their correct operation for a long time. To avoid the appearance of dark spots, streaks on the screen of a plasma, liquid crystal TV, follow these recommendations:

Taking care of your LCD or plasma TV in this way will save you from the appearance of dark spots on the screen. Try to avoid mechanical damage. Explain to the children that technology is not a toy. And enjoy digital TV for years on end.

Light, colored spots and streaks are removed by other methods. General repair method only in cases with software failure. Therefore, if any screen defects appear, just try to completely restart the equipment and reset the router to factory settings.

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 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.

A comparison between a blank passive-matrix display (top) and a blank active-matrix display (bottom). A passive-matrix display can be identified when the blank background is more grey in appearance than the crisper active-matrix display, fog appears on all edges of the screen, and while pictures appear to be fading on the screen.

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.

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.

Color performance: There are multiple terms to describe different aspects of color performance of a display. Color gamut is the range of colors that can be displayed, and color depth, which is the fineness with which the color range is divided. Color gamut is a relatively straight forward feature, but it is rarely discussed in marketing materials except at the professional level. Having a color range that exceeds the content being shown on the screen has no benefits, so displays are only made to perform within or below the range of a certain specification.white point and gamma correction, which describe what color white is and how the other colors are displayed relative to white.

Brightness and contrast ratio: Contrast ratio is the ratio of the brightness of a full-on pixel to a full-off pixel. The LCD itself is only a light valve and does not generate light; the light comes from a backlight that is either fluorescent or a set of LEDs. Brightness is usually stated as the maximum light output of the LCD, which can vary greatly based on the transparency of the LCD and the brightness of the backlight. Brighter backlight allows stronger contrast and higher dynamic range (HDR displays are graded in peak luminance), but there is always a trade-off between brightness and power consumption.

Usually no refresh-rate flicker, because the LCD pixels hold their state between refreshes (which are usually done at 200 Hz or faster, regardless of the input refresh rate).

No theoretical resolution limit. When multiple LCD panels are used together to create a single canvas, each additional panel increases the total resolution of the display, which is commonly called stacked resolution.

LCDs can be made transparent and flexible, but they cannot emit light without a backlight like OLED and microLED, which are other technologies that can also be made flexible and transparent.

As an inherently digital device, the LCD can natively display digital data from a DVI or HDMI connection without requiring conversion to analog. Some LCD panels have native fiber optic inputs in addition to DVI and HDMI.

Limited viewing angle in some older or cheaper monitors, causing color, saturation, contrast and brightness to vary with user position, even within the intended viewing angle. Special films can be used to increase the viewing angles of LCDs.

As of 2012, most implementations of LCD backlighting use pulse-width modulation (PWM) to dim the display,CRT monitor at 85 Hz refresh rate would (this is because the entire screen is strobing on and off rather than a CRT"s phosphor sustained dot which continually scans across the display, leaving some part of the display always lit), causing severe eye-strain for some people.LED-backlit monitors, because the LEDs switch on and off faster than a CCFL lamp.

Only one native resolution. Displaying any other resolution either requires a video scaler, causing blurriness and jagged edges, or running the display at native resolution using 1:1 pixel mapping, causing the image either not to fill the screen (letterboxed display), or to run off the lower or right edges of the screen.

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.

Dead or stuck pixels may occur during manufacturing or after a period of use. A stuck pixel will glow with color even on an all-black screen, while a dead one will always remain black.

In a constant-on situation, thermalization may occur in case of bad thermal management, in which part of the screen has overheated and looks discolored compared to the rest of the screen.

Loss of brightness and much slower response times in low temperature environments. In sub-zero environments, LCD screens may cease to function without the use of supplemental heating.

The production of LCD screens uses nitrogen trifluoride (NF3) as an etching fluid during the production of the thin-film components. NF3 is a potent greenhouse gas, and its relatively long half-life may make it a potentially harmful contributor to global warming. A report in Geophysical Research Letters suggested that its effects were theoretically much greater than better-known sources of greenhouse gasses like carbon dioxide. As NF3 was not in widespread use at the time, it was not made part of the Kyoto Protocols and has been deemed "the missing greenhouse gas".

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You have discovered a black spot on your laptop screen, and you are not alone! Finding a black mark on your LCD can be disheartening, but there are steps you can take to get rid of it. So, if you are here to know how to fix black spots on a laptop, do not skip any part of this article and read until the end.

The black spots are just surface blemishes that appear when dirt or other particles lie on the glass of your screen or due to some defects with the LCD pixels. They are not cracks or tears that may cause the display to fail in the near future, and it’s certainly not an indication of broken glass. Although these can easily be fixed, it is crucial to have a proper understanding of what causes the spots so you can take measures to prevent them from appearing again in the future.

A laptop or LCD monitor’s screen is like a mirror, and it reflects the light from your computer’s display back at you. Black spots on display occur when small amounts of dirt and dust or smudges gather and are stuck to the surface.

Sometimes, dirt or debris may accumulate on your laptop screen, which leads to black spots that become visible to the naked eye and grow larger over time and can cause problems with screen resolution if left untreated.

These spots are typically easy to remove without damaging the monitor. However, failing to clean the dirt or debris on a regular basis, more of them will appear and gradually obscure more of your laptop’s screen, making the rest of the screen appear duller by comparison.

Though such black marks will not reduce the quality of the display of your LCD screen and cause any damage to the internal circuit of the monitor, they are very annoying.

The easy solution to get rid of these spots is to clean your screen with a moderately dampened microfiber cloth or soft eraser. Make sure you do not apply pressure while rubbing the display; instead, wipe it with gentle and circular strokes to avoid scratches and leftover marks.

Different types of pixel defects happen on LCD screens, including dead pixels and stuck pixels. Identifying the problem correctly will help you to choose the right methods to fix it that will not result in damaging the screen any further.

Most laptops have some pixel problems in them. The number of defective pixels you see depends on the screen resolution – the smaller the resolution, the larger they seem. In most cases, they are not noticeable during regular use as they are not bright spots, and if your laptop is free from pixel issues when you buy it, consider yourself lucky.

LCD manufacturing technology has improved dramatically over the years, and today’s panels almost don’t come with any such problem. However, as earlier as a few years back, there were times when defective pixels or vertical/horizontal lines would be let out into the market for lower-cost models.

When a pixel gets permanently damaged, it fails to receive power, resulting in a dark or black spot on your laptop display. This specific malfunction can occur during the manufacturing process of LCD monitors, and it is sort of permanent, which does not recover over time.

However, one can rarely experience such defects on their laptop screens out of the box since manufacturers strive to follow stringent quality control processes to make sure they deliver a flawless product. On the other hand, it’s quite normal to notice dead pixels appearing on the screen over time, depending on multiple usage factors.

Every modern laptop comes with a built-in LCD diagnostic mode that can successfully identify any pixel malfunction on your laptop’s screen. Follow the step-by-step method as below –

Now, turn the laptop on while pressing and holding the D key at the same time, and you will be taken to the self-test mode. Do not release the D key until the color bars appear on the LCD.

However, it’s tricky to differentiate between dead and stuck pixels by naked eyes; therefore, you may want to look for other ways. If you are using a Windows laptop, install a free software named “InjuredPixels” – you can Google for its official website and download from there. Or if it’s a Mac, “LCD DeadPixel Test” is a browser-based tool (so nothing to download or install) that can help.

Spotting any defective pixel is relatively easy using these apps. They run single solid colors on your display so that you can quickly find out the malfunctioning pixel that doesn’t match the color of the rest of the screen real estate. You can further ensure whether it is a dead or stuck pixel before you attempt to fix it.

The common causes of an LCD monitor having a bad pixel are the following: extremely high or low temperature, a sudden drop in voltage, high levels of humidity, and static display over an extended period.

Keeping your laptop unprotected close to a heating source can force the pixels on the LCD to get solidified. Even lower temperatures below the allowed limit can lead to the same result.

Read the user manual for the ideal range of humidity levels within which you should operate your laptop. Keeping your LCD screen powered on in a high level of humidity may cause tiny droplets of moisture to enter the inside exposed areas of your display, resulting in a pixel malfunction.

If you find that your LCD panel display has dead pixels, there are a few things you can try. One of the simplest things to try is rubbing it gently, particularly if the dead pixel is on the edge of your screen where it is barely noticeable.

Before you try this technique, your LCD panel must be clean and free of dust and debris. Simply wiping with a soft cloth should remove most dirt and smudges. Also, using an object with a circular end, such as a smartphone stylus, and placing a soft microfiber cloth over the problem spot during the process will greatly reduce the risk of causing more harm to the screen.

JScreenFix is a website that can help you with your dead or stuck pixel issues. No expensive equipment or software is required as using the site is 100% free. All you need is just your laptop and an internet connection, and you are good to go. Below is a step-by-step guide that will walk you through the steps to solve the problem!

You would be in luck if your laptop was still under warranty period when you noticed the pixel defect. Take the unit to the official service center or the retailer you purchased it from and ask about the warranty claim process. In the majority of cases, any such pixel damages are considered manufacturing defects, and the company will simply replace the LCD.

It depends. If you are experiencing a stuck pixel problem on your screen, it will likely recover by itself after a while in the majority of cases, without any user input. On the other hand, a dead pixel is more or less a permanent condition.

For stuck pixels, you have little to worry about as they usually disappear over time. However, dead pixels are mostly not user repairable. With that’s being said, JScreenFix and PixelHealer are two incredibly effective software solutions that you can use to restore your stuck and dead pixels – experts found their success rates pretty high.

Before you start looking for how to fix black spots on a laptop, it’s crucial to figure out exactly what caused the condition. Typically the issues people face are minor, and the black spots on their screens are a result of dust and dirt accumulation, which can be fixed with a simple cleaning.

The easy solution to get rid of these spots is to clean your screen with a moderately dampened microfiber cloth or soft eraser. Make sure you do not apply pressure while rubbing the display; instead, wipe it with gentle and circular strokes to avoid scratches and leftover marks.

Fixing black spots on your TV screen is quite simple. First, turn off your television and unplug it from the power source for a few hours. Sometimes, turning off the power on your TV will force the stuck pixel to become unstuck when you finally plug your TV back to the mains.

Black dot is usually an indication of a dead pixel and depending on what cause the dead pixel yes it could spread. It could eventually spread across the whole screen. Get your phone checked out and go from there. If it is a damaged panel then get it replaced.

Do Dead Pixels Spread? Dead pixels usually don"t spread. They"re usually a small fault in a display. If they do spread, you might need to hire a specialist or replace your screen.

Pixel bleeding is an indicator that the LCD has sustained significant damage. Even if it"s not that bad right now, it will be soon. Unfortunately, it"s a sure thing that it will get worse over time. Regardless of how bad the pixel bleed is, the entire LCD will need to be replaced.

Apply pressure to the area where the stuck pixel is. Try not to put pressure anywhere else, as this may trigger the creation of more stuck pixels. While applying pressure, turn on your computer and screen. Remove pressure, and the stuck pixel should be gone.

To recap, black spots on LCDs are typically caused by either superficial dirt or debris, a stuck pixel or a dead pixel. The easiest problem to fix, of course, is a superficial dirt or debris. In comparison, stuck pixels are a little harder to fix, whereas dead pixels are the hardest to fix.

If the screen is discolored, use a pen cap to lightly rub the screen in the discolored area. If the issue is stuck pixels, applying mild pressure to the screen might fix it. If you have a slider-style phone with a white screen, the issue could be a ribbon cable that has worn out or moved out of its socket.

You will often be able to get a cracked screen repaired at a local authorized repair shop. The price will vary depending on which model Pixel you are getting repaired. Screen repair on a Pixel will run from about $129 - $299, and screen repair on a Pixel XL will run from about $149 - $309.

Can backlight bleed go away on its own? Sometimes. All LCD screens have some backlight bleed at first, but as the pressure around the panel weakens with use, it will become less noticeable. If you"ve had your device for a while, the backlight bleed probably isn"t going away.

When the black spot is spreading on your phone screen, you need to have the screen replaced. If you try to repair the phone yourself, you may cause more damage to it, thus complicating the issue. Hence, seek the help of professionals.

The 100,000-hour figure assumes that every diode will be running at full brightness, consistently — which, on an LED screen, is virtually never the case. The lifespan figure can also be misleading because it indicates when a diode degrades to half-brightness, not completely dark. Many other variables affect an LED display’s lifespan; you can’t rely solely on the number on the diode spec sheet.

“The reality is, your screen can often last significantly longer than 100,000 hours,” says Kevin Izatt, a senior product manager in Samsung’s Display division. “We’ve had displays that have been up for 15-plus years with more than adequate brightness. Because the diode is actually only one factor in the lifespan of your LED display.”

The quality of your display’s power supply — and how hard it drives the diodes — can have a significant impact on your screen’s lifespan. The other components being powered, such as fans and electrical components, have their own lifespans as well, which are also impacted by the power supply.

“Something like airflow is very important,” says Izatt. “You need a screen that has good cooling, and a design that allows heat to flow out of the back through vents.”

To help businesses transition from LCD to longer-lasting LED signage, Samsung has launched a trade-in program. Samsung will come on site to remove your existing display and provide a discount on a new LED bundle kit.

Traded-in LCD displays that are still operating will be refurbished and resold, and your business will receive a cash rebate. Nonworking displays will be recycled and their parts reused.

As you plan your LED signage rollout — or an upgrade — learn how to configure and tailor your screens’ real-time messaging with an integrated CMS in thisfree guide. And if you haven’t decided what kind of display is best suited to your current project, compare all ofSamsung’s LED displays.