how do you clean an lcd screen tv made in china
What can be better after a long day’s work than lying down on a sofa watching TV? The television can become our best friend to relieve the pressure from work, relationships, and annoying relatives. LCD TV displays as added “member” of the family also need to be taken care of. For this reason, it is recommended to regularly clean the LCD screen as dust and dirt may affect its performance. What we are trying to say is that if the television is too dirty, you won’t be enjoying your favorite program. Trust me! you do not want that…
How can we clean the LCD Display? This is a concern for many people. Before we find out the answer, we need to know what to avoid. Here, please do not take out your t-shirt and wipe the screen from those beer stains, calm down, and hear me out. Many people would easily make mistakes in solving this problem even without consciousness. So let’s take a look at some wrong cleaning methods first: Wiping the LCD Screen directly with the palm or fingers
You should know that LCD should not be touched. When rubbing with the palm or fingers, it is difficult to use the right amount of force. If the force is too strong, it may cause permanent damage to the liquid crystal molecules, which translate into watching at a multicolor liquid stain on your TV instead of your favorite show. Wipe the LCD screen with a rough towel
Someone may directly clean the LCD display with the towel used to wipe the table at home. However, this is a wrong behavior as you can scratch the surface or get the screen even dirtier. Do not also use paper towels, toilet paper, or old T-shirts. These materials are abrasive and leave a lot of residues.
Now that we know what we should not do, let us move with the proper cleaning methods. First of all, let us briefly explain the LCD TV display structure. The LCD panel is mainly composed of two sodium-free glass sandwiched by a polarizer, a liquid crystal layer, and a color filter. Feeling confused? check here our article about LCD TVdisplays.
Moving on to the cleaning. Well, the first thing you should do is to turn off your television. I know it seems obvious to say, but many people do not follow this step. After that, you have two main choices: standard or creative method:
The first being the standard option, is the most formal and troublesome. Stand up and go out buying the special LCD cleaner and microfiber cloth to clean the LCD screen. If you are too lazy, you can order it online. Although this method is effective, it implies that you need to buy the cleaning agent and my friend, depending on how regularly you clean, it can be expensive. Once bought the products, apply the cleaning agent to the cloth and gently wipe the entire surface of the LCD TV display, removing any visible traces of dirt and dust.
If you thought it was too easy after hearing the standard option, or those nasty stains are still there, we have the solution for you. Here we share the “creative” method.
Prepare a liquid solution using equal amounts of vinegar and water. Vinegar is a natural and safe detergent and is much cheaper than the products on the market, specially designed for cleaning televisions.
Dampen the microfiber cloth in the vinegar and water solution and then wipe your TV screen softly. If necessary, apply gentle pressure and a circular motion to the spots where you notice stubborn stains. Keep in mind not to spray the vinegar solution directly on the TV screen, as you could damage it irreparably.
Following, use a second microfiber cloth to dry the TV screen. Pay attention not to allow the screen to air dry. Otherwise, annoying halos may remain and influence image quality.
Finally, wash the plastic frame of the TV. If the frame also requires a more intensive cleaning, use some paper towels after wetting it in the vinegar and water solution. Use paper towels to dry it completely.
To better enjoy your LCD TV display, you need to take good care of it. Our team at Aiwa is devoted to developing innovative solutions for visual entertainment with LCD TV, LCD monitors, and other electronic devices. Our product offers a longer life-span and longevity.
Television screens are supposed to be clean and free of dirt, dust, or any debris that may blur vision. This is why this component is one of the most vital parts of a Television. Nothing can be worse than straining your eyes to make sense of the pictures your set is projecting. If you do not clean your TV regularly, fingerprint smudges and dust will build up.
Cleaning your LED TV or any type of television for that matter is something you should do at least once every 2 or 3 weeks. In fact, I will suggest that you do it as often as you watch it any paying more attention to the screen when you do so. If you clean your TV set regularly, it will always look brand new, and you will enjoy bright and colorful pictures without said. Bearing that in mind, there are ways to go about a cleaning endeavor. Unfortunately, not everyone knows how to clean a set effectively. Many think that a piece of towel soaked in water will do. How wrong they are. Television screens are very sensitive, so a great deal of care is required to do the job effectively. In addition to that, being careful also protects the screen for damage. Secondly, you need to understand that TV sets are different. Although they all project sounds and images, they are built differently. So, therefore, the approach to cleaning should also be different as well.
The approach to cleaning an LED TV screen, for instance, requires extra care compared to the cleaning of a Tube TV. They both have screens, but the former is more sensitive than the latter due to the sensitivity of LED screens build material. Bearing all this in mind, how do you safely clean an LED TV screen without damaging it in the process. In this article, we will show you safe and intelligent ways to go about it using available and affordable materials. You will also learn a few tips about how to do it safely too.
Before you proceed, you need to bear two things in mind when cleaning LED TV screens. Firstly, you want to do it in such a way and with the right materials that ensure the screen is clean and devoid of dust or stains of any kind. You want your screen to be as bright and clear as possible. Secondly, you want to avoid damaging the screen or reducing its projection quality. This is why it is necessary to use only the right cleaning materials and approach at all times. Now, here are some helpful tips for adopting when cleaning an LED television screen. [/fusion_text]
Every electronic equipment comes with an owner’s manual. This manual provides the user with sufficient information about how to use and maintain the gadget. The same thing goes for LED sets. They come with an owner’s manual too. Before you clean the set, you may want to read the manual first.
In fact, it is advisable that you read it first immediately you buy and install it in your home. By reading the manual, you gain more understanding regarding how to care for the television all through it a lifespan in your home, office, or wherever you install it. For the purpose of cleaning, pay attention to the section that provides information about how to do it effectively.
Reading manuals is important because different television manufacturers provide different approaches to cleaning their sets. What works for an LG LED TV may not work for a Samsung set. That is why it is so important to only follow the recommendation of a one cap fits all approach to cleaning your TV screen. If you read the manual when you bought it, but you have forgotten the cleaning details, consult it once again to refresh your memory.
Before you start the cleaning properly, turn off the television set. Do not stop at that. You also need to unplug it from the power source. Once you have done that, do not start cleaning the screen immediately. Give it time to cool down. The cleaning process may take between 2-5 minutes or even more depend on your LED TV model or how long it was on.
Turning the TV off will cut off power leading to the cooling down of the screen. You don’t want to be cleaning a hot or warm screen, do you? You want to make sure that the screen is as cool as possible and non-reactive to whichever cleaning agent you use.
Another advice to take in that is so important is that you should never use paper towels to clean the screen. There are reasons to avoid paper towels. Paper towels, especially when soaked in water, leave smudges and stains on the screen. No matter how long or how hard you try to wipe the marks off, they yet remain. Paper towels are bad for your TV screen. It’s as simple as that.
To enjoy an ultimate cleaning experience, you should consider using microfiber cleaning pieces. Some people recommend cotton whole because they are more breathable. However, microfiber cloths are more durable. In addition, they do not stick to your screen. Older LED, or LCD screens can’t handle traditional cleaning methods or materials. With microfiber, you can eliminate stains, remove smudges, and fingerprints with ease.
To use microfiber, simply wipe the surface of the screen in a circular motion. Cover as much part of the screen as you possibly can. Work your way around the edges as well. More importantly, when cleaning, avoid touching the screen with your bare hands as doing so will leave fingerprint marks on it.
The use of chemicals should be avoided at all costs. Chemicals damage screens more than you know. That a chemical agent worked on a particular surface is not an indication that it will work well for your TV screen. LED screens are very sensitive and fragile, so you ought to make sure that you keep chemicals as far away as possible. Another material you should never use is a detergent solution (water and detergent).
Soap, scouring powder, was window cleaners, and any other general industrial cleaner should be avoided. Abrasive pads and towels made from paper should not be used either. Using any of these materials will lead to screen scratches, anti-glare coating damage, or permanent screen damage. The sad part is that the damage may not be noticeable at first, but over time, the same will become permanent.
If you must wet your cleaning material with water, do so in little splashes. Avoid spraying the screen directly with water. When wiping the screen, do so gently because it can break if pressed too hard as screens are very fragile.
You will notice that your microfiber cloth cannot reach the edges of the screen like the other areas. If you don’t clean the edges too, dust and first will accumulate in those parts, and after a time removing the stains will love difficult. Furthermore, failure to clean screen edges will lead to an uneven appearance, with poor picture quality being the end result. To clean edges and corners effectively, use cotton swabs to greater effect. For better results, dab the cotton swabs in water. Pick off the dirt carefully by dragging them out using the swabs. Do this for the four corners of the screen.
As for the edges, run the swabs up and down systematically but avoid running them all the way down to the edges as this may drive dirt further on that may be difficult to remove. For better results, use as many cotton swabs as you can.
Unlike an LED TV screen, cleaning a Tube TV is much easier. Tube TV screens are more rugged and can withstand pressure, but doing so carefully is also important. You can use a microfiber cleaning cloth doused in a little water. Never spray the screen directly as this may damage it. Rather, work your way with the microfiber cloth. Apply the same circular cleaning motion like you would do an LED TV screen. Cotton swabs will also come in handy to pick off the dirt from the screen corners.
Dish soap can also be used on LED and LCD screens, albeit with care. Before you use a dish soap solution, first wipe the screen with a dry cloth to remove dust. Now, dip your cleaning cloth in the dish soap solution. Squeeze off the liquid then gently wipe the screen. Make sure you cover every surface area. Once you are done, don’t waste time to clean; otherwise, the solution will dry up on the screen leading to a blurry vision. Rinse the cloth with water to remove soapy residue then take the dry cloth you used to wipe off the dust once again to dry the screen.
Yes, they do. There are actually cleaners specially made for cleaning tv screens. Screen cleaners contain distilled water, isopropyl, and alcohol solutions. If you must use an electronic screen cleaner, make sure you shake to content before use. Also, apply on a limited portion of your cleaning cloth.
Cleaning your TV remote control is part of a general TV cleaning process. So to clean your remote control, follow these tips. Pop-out the batteries:Remove the batteries from the remote. Doing so will create enough room when cleaning the interior casing.
Tap the remote lightly on a hard surface:Remote controls gather a lot of dust and debris along the way. To remove them, tap the remote control on a hard surface like a table. Do this gently and several times to dislodge debris stuck in crevices.
Use a mild disinfectant:Apply a cleaning disinfectant on a piece of cloth and clean the body thoroughly. The use of disinfectant is necessary because our hands carry germs, and we transfer these germs to the remote control anytime we operate it. Clean the whole body thoroughly.
Maintain a weekly timetable:To ensure that your TV set is always clean, make sure you clean it weekly. Add it as part of your to-do list when cleaning your home. If your furniture deserves regular cleaning, so does your television set. Doing regular cleaning will atop dust, debris and fingerprints from smearing the screen. It is also much easier to clean when there is little dust on the surface. Keeping a microfiber cloth close by is also advised so that you can quickly wipe off dust when necessary.
Never spray your LED TVset directly with any substance:Avoid spraying your screen directly with any substance even if it is an electronic cleaning gel. Excessive spraying can damage the cabinet and the structural make-up of the screen. If you must use any cleaning solution, apply it on the napkin or microfiber cloth you are using and gently wipe the screen with it.
Use a Vacuum:To draw out dust and debris hidden in the crevices of the set, use a low suction vacuum. You may also use the vacuum cleaner’s soft brush to remove dust from the cable, vents, and ports of the TV
Adhere strictly to the User Manual:Your LED TV set comes with a user manual for a reason. The manual is meant to guide your use of the device. When cleaning your set, make sure you follow the directives of the manufacturer. Doing it any other way may damage the TV beyond repair.
Avoid strong cleaning agents:Just like we pointed out in the article, avoid strong cleaning agent as not all of them are good for your television’s screen. The screen is very sensitive, so bear this in mind. Some examples of cleaning agents to avoid include unmixed alcohol, ammonia, acetone, and Wax.
Maintaining your LED TV set requires a lot of patience and attention to detail. If you want the screen to remain in good shape, you need to clean it regularly and with proper cleaning materials. If you follow the tips in this article, your screen will remain bright and sharp for as long as you use the set.
Screens can scratch easily, and even paper towels and tissues contain fibers that can do damage. “Your best bet is to use a soft, anti-static microfiber cloth—the kind used to clean eyeglasses and camera lenses—and wipe in a circular motion,” says John Walsh, who cleans more than 250 TVs a year in his role as a CR photographer. (Some TV manufacturers will include a cloth for this purpose.) “Gently wipe the screen with a dry cloth to remove dust and other debris, but don’t press too hard,” he says.
You may also want to wipe down the TV’s cabinet, and make sure dust isn’t clogging the vents that help dissipate heat. If the TV is on a stand and not tethered to the wall, Walsh suggests cleaning with one hand while supporting the TV with the other to prevent the set from tipping over. However, CR strongly recommends anchoring all stand-mounted TVs using anti-tipping straps designed for this purpose.
If there are hard-to-remove stains, you can dampen the cloth slightly with distilled water and gently clean the screen. Don’t spray water directly onto the screen; that could cause a shock or component failure if water seeps into the inner workings of the set.
For the most stubborn stains, you can try using a solution of very mild dish soap highly diluted with water, once again applied to the cloth and not to the TV itself. (As a guideline, Panasonic used to recommend a 100:1 ratio of water to soap.) LCD screens, in particular, are very sensitive to pressure and can scratch easily, so don’t press hard.
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Modern flat screen TV"s have a known problem with capacitors going bad. If your LCD or LED TV won"t turn on, or makes repeated clicking sounds, there is a very good chance that you can save hundreds of dollars doing this simple repair yourself.
I know, I know. You"re thinking, "Tinker inside my LCD HDTV. Are you crazy?" No, I"m not crazy. This is a repair almost anyone can do and this fix will work for any TV.
You sit down and get comfortable, ready to watch your favorite TV show or movie. You turn on your TV and...nothing! Unsure if you hit the power button, you try again...again, nothing! But you do notice a clicking sound emanating from your TV.
HDTV"s aren"t cheap. Most of us have to save, or at least be prepared to spend $800-$1000 on new one. Heck, I"m sure many of you don"t savor the idea of spending a few hundred on repairs.
I have good news. This repair is actually quite simple, and with only a few basic tools and about 20 bucks, you can have your TV working in less than an hour.
The bad News. If your TV is physically damaged in any way, been dropped, has a broken screen or gotten wet then this repair isn"t for you. But if your TV was working one day but not the next, read on.
If you need a soldering iron, that no problem. They are cheap and easy to use. I highly recommend this 60 Watts Soldering Iron Kit. It"s less than 20 bucks. If your looking for the lowest price possible, this 60W soldering iron with stand is about $8 (shipped prime) and will work fine.
After unplugging everything on the TV, you will need to remove the stand. If your TV was wall mounted you will need to remove the TV from the wall, and remove the mounting bracket from the back of the TV.
The TV sits on top and inside the stand, so it wont just flop over when you remove the stand screws, but it"s always safer to have a friend hold the TV upright as you remove the screws from the stand. Then each of you grab a side and carefully lay it flat on a carpeted surface.
Above is a a picture of the back side of a typical TV. The left picture is my LG 42LN5300 and the right picture is my Samsung LN46A550, but all TVs are similar. Remove all of the screws along the outer edge of the back casing. There can be anywhere from 10 - 16 of these screws.
There will also be screws within any area where the are power or cord plugins. You can see these in the lower middle of the pictures. (highlighted with the red rectangle on my Samsung)
Then identify the "power board". Every TV is a little different, but the power board will have can shaped capacitors and is the board that the main power from the plug goes to first. On this Samsung TV I put a green rectangle around the power board that we will be working on..
The other "green" board is the "logic board", this is the computer that runs the TV. Repair of the board is beyond the scope of this article. (But it"s most likely not the problem)
Remove the screws holding the power board to the TV chassis. Most boards will have 6 screws holding them down, as does the one shown in the picture. But look it over there could be more or less.
This TV repair focuses on the small "can shaped" Aluminum ElectrolyticCapacitors.These capacitors come in many colors and sizes but are easy to find on any power board. Not only are these the most likely cause of your problem, but bad ones are simple to find and simple to replace. In most instances you will be able to visually identify the bad capacitors. You don"t need any special skills in electronics or testing.
When a Capacitor fails, the chemical reaction inside the capacitor can produce hydrogen gas, so capacitors have vents cut into the tops of their aluminum cans. These are intended to break and release the gas that has built up inside the capacitor. So, a capacitor which has failed can show bulging at the top..
Another sign of a failed capacitor is leaking fluid (electrolyte). This can be an orange or brownish discharge from either the top or bottom of the capacitor. Usually, with leaking the capacitor will also be bulging. But a capacitor can bulge but not leak.
Capacitors do not always show visible signs of failure. But, if you see either of the 2 signs above on your board, you can be confident that you"re close to fixing your TV. If you don"t see these signs of failure, but your TV had the tell-tail clicking sound, you still can be fairly certain the steps below will fix your TV.
On power board pictured above, I have indicated which capacitors you should be examining for signs of failure. These Capacitors are Aluminum Electrolytic Capacitors, and are the most likely cause of your problem. The capacitors with the green arrows are the most likely candidates for being bad, but the blue arrow are other capacitors to examine.
Warning: Do not bother with the large capacitors (2 or 3 will be on every board). These are high voltage, rarely fail and for safety require a little more expertise to work on.
The pictures above are actual closeups of my TV"s board. Notice how the blue capacitors in the foreground are bulging. These are the capacitors I will replace. All other capacitors look OK. If you can find replacements for all 4 of these capacitors, and any others that show visual signs of going bad, I recommend replacing them all while your in here.
Capacitors have polarity. What this means is, like a battery, they have a positive (+) and a negative (-) side. Before removing any capacitor, note which side the white stripe of the capacitor is facing. You will need to put in the new capacitor in the same direction. You probably noted on my pictures that I actually made a note on the aluminum heat sink with a pen.
Now that you"ve identified the capacitors that look bad, turn the board over and carefully identify exactly which points on the board are the wire leads from the these capacitors.
Circle them with a "sharpie" type pen to keep track. Grab your friend and have them help you on this next step. Balancing the circuit board on its side while using a hot soldering iron and pliers can be a bit tricky.
With the circuit board on its edge, have your friend grab one of the capacitors with the pliers and apply a very gentle pulling pressure. Apply the tip of the soldering iron to one lead on the back side of the board and hold it there until you see the solder melt. Now switch to the other lead until it melts. Keep going back and forth on the leads. Each time the solder will melt faster. After going back and forth a couple times the capacitor will easily come out.
Ideally you should match the uF and the temperature rating exactly. But it is acceptable to use a capacitor rated higher uF if it is within 20% of the original.
Place your soldering iron and solder on lead until the heat melts the solder. Once solder melts onto the lead, apply the iron on the lead and solder a few times to melt the solder cleanly on the lead. If you have solder flux, the solder will make a clean connection.
So I took my tv apart and I think I found the problem can you please verify for me? Pictures attached. I think one of the big CAPACITOR is bad and leaking on the bottom of the board is brown.
I have a Samsung LN-T4066F that keeps clicking like it"s trying to turn on, but won"t. It"s plugged into a surge protector so I just turn that off to make it stop. Every few hours, I turn the switch on the surge protector and once in a while the TV turns on! Can it be the capacitors?More CommentsPost Comment
As the weather warms, it"s time for everyone"s "favorite" pastime: spring cleaning. While you"re dusting off the shelves and shoveling out a winter"s worth of detritus, spare a moment to check your TV. Dust and grime can accumulate there, and over time it can become more and more noticeable. And if you have children, there may be an array of fingerprints and other smears on the screen.
The short version? Don"t use liquids, don"t press too hard, don"t use any traditional cleaners. Microfiber cloths are good, but be gentle. Modern TVs are predominantly plastic and therefore far easier to scratch than windows or your phone.
Want the longer version? Here"s what the top TV manufacturers say about cleaning their screens:Cleaning your 4K, OLED, or LED TV screen with a soft, dry cloth is recommended. The goal here is to avoid scratching the screen. Gentle, circular motions tend to give better results, since the circular motion hits each area from several angles in a single swipe.
Caution: Don"t spray water or other liquids directly on the TV, as electric shock could occur.Turn the TV off and let it cool down for a few minutes before unplugging it.
To clean the frame and screen, gently wipe it with a microfiber cleaning cloth. Make sure to wipe the TV frame and screen as gently as possible. TV screens are fragile and can be damaged when pressed too hard.
Important: Never use any type of window cleaner, soap, scouring powder, wax, or any cleanser with solvents such as alcohol, benzene, ammonia, or acetone. Never use abrasive pads or paper towels. If you do, you can scratch the screen or strip the anti-glare coating off the screen and cause permanent damage. Never spray water directly onto the TV. Make sure to wipe the TV as gently as possible. TV screens are fragile and can be damaged when pressed too hard.Gently wipe the screen or the exterior with a dry, soft cloth, such as an eyeglass cleaner.
For inks from oil markers on the screen, soak a cloth in a non-soap synthetic cleanser diluted (by less than 1% ) with water. Squeeze the cloth tightly to eliminate excess liquid, then wipe gently to remove the ink. Use non-soap cleansers cautiously because it may cause environmental problems when disposed improperly.
So why not Windex? Regular Windex is formulated for glass windows, plus a few other surfaces. It contains ammonia and alcohol, not the friendliest of chemicals. S. C. Johnson doesn"t explicitly say not to use Windex on TVs, but it offers Windex Electronics wipes and cleaners, so infer what you will. The better screen cleaners will clearly state that they do not contain alcohol or ammonia.
At last count, I found a billion companies making TV screen cleaners. Almost all of these are something like 99 percent water, 1 percent other stuff. Years ago I tested a handful and found them, on average, to work well enough. If you don"t have luck with a simple cloth and possibly distilled water, a screen cleaner is worth a try, and as a bonus you can also use it for your laptop, tablet and cell phone screens. Plus, they come with a microfiber cloth. If they don"t clearly state they don"t contain alcohol and ammonia, however, I would skip them.
So yeah, cleaning your TV is a good idea. But just remember that they"re exceptionally fragile. Why risk marring their surface by using cleaning methods the companies themselves don"t advise? If you damage your screen with cleaners, you won"t be able to fix it.
My advice? Get a nice microfiber cloth (if your TV didn"t come with one), and use that. If that doesn"t fix your smudges, try a cloth moist with water. Don"t press too hard. There"s less than a millimeter between your finger and a broken TV.
Screen cleaning kits are fine, though most people won"t need them. Remember, like all TV accessories, the store is selling them because they probably make more profit on that $20 kit than on a $500 TV.
As well as covering TV and other display tech, Geoff does photo tours of cool museums and locations around the world, including nuclear submarines, massive aircraft carriers, medieval castles, epic 10,000 mile road trips, and more. Check out Tech Treks for all his tours and adventures.
He wrote a bestselling sci-fi novel about city-size submarines, along with a sequel. You can follow his adventures on Instagram and his YouTube channel.
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 directly,backlight 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, digital clocks, calculators, and mobile telephones, including smartphones. LCD screens are also used on consumer electronics products such as DVD players, video game devices and clocks. LCD screens have replaced heavy, bulky cathode-ray tube (CRT) displays in nearly all applications. LCD screens are available in a wider range of screen sizes than CRT and plasma displays, with LCD screens available in sizes ranging from tiny digital watches to very large television receivers. LCDs are slowly being replaced by OLEDs, which can be easily made into different shapes, and have a lower response time, wider color gamut, virtually infinite color contrast and viewing angles, lower weight for a given display size and a slimmer profile (because OLEDs use a single glass or plastic panel whereas LCDs use two glass panels; the thickness of the panels increases with size but the increase is more noticeable on LCDs) and potentially lower power consumption (as the display is only "on" where needed and there is no backlight). OLEDs, however, are more expensive for a given display size due to the very expensive electroluminescent materials or phosphors that they use. Also due to the use of phosphors, OLEDs suffer from screen burn-in and there is currently no way to recycle OLED displays, whereas LCD panels can be recycled, although the technology required to recycle LCDs is not yet widespread. Attempts to maintain the competitiveness of LCDs are quantum dot displays, marketed as SUHD, QLED or Triluminos, which are displays with blue LED backlighting and a Quantum-dot enhancement film (QDEF) that converts part of the blue light into red and green, offering similar performance to an OLED display at a lower price, but the quantum dot layer that gives these displays their characteristics can not yet be recycled.
Since LCD screens do not use phosphors, they rarely suffer 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 are, however, susceptible to image persistence.battery-powered electronic equipment more efficiently than a CRT can be. By 2008, annual sales of televisions with LCD screens exceeded sales of CRT units worldwide, and the CRT became obsolete for most purposes.
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, along with OLED displays, 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.
The origins and 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.IEEE History Center.Peter J. Wild, can be found at 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 at a meeting of the Vienna Chemical Society on May 3, 1888 (F. Reinitzer: Beiträge zur Kenntniss des Cholesterins, Monatshefte für Chemie (Wien) 9, 421–441 (1888)).Otto Lehmann published his work "Flüssige Kristalle" (Liquid Crystals). In 1911, Charles Mauguin first experimented with liquid crystals confined between plates in thin layers.
In 1922, Georges Friedel described the structure and properties of liquid crystals and classified them in three types (nematics, smectics and cholesterics). In 1927, Vsevolod Frederiks devised the electrically switched light valve, called the Fréedericksz transition, the essential effect of all LCD technology. In 1936, the Marconi Wireless Telegraph company patented the first practical application of the technology, "The Liquid Crystal Light Valve". In 1962, the first major English language publication Molecular Structure and Properties of Liquid Crystals was published by Dr. George W. Gray.RCA found that liquid crystals had some interesting electro-optic characteristics and he realized an electro-optical effect by generating stripe-patterns in a thin layer of liquid crystal material by the application of a voltage. This effect is based on an electro-hydrodynamic instability forming what are now called "Williams domains" inside the liquid crystal.
The MOSFET (metal-oxide-semiconductor field-effect transistor) was invented by Mohamed M. Atalla and Dawon Kahng at Bell Labs in 1959, and presented in 1960.Paul K. Weimer at RCA developed the thin-film transistor (TFT) in 1962.
In 1964, George H. Heilmeier, then working at the RCA laboratories on the effect discovered by Williams achieved 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 George H. Heilmeier was inducted in the National Inventors Hall of FameIEEE Milestone.
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,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.
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.
Mini-LED: Backlighting with Mini-LEDs can support over a thousand of Full-area Local Area Dimming (FLAD) zones. This allows deeper blacks and higher contrast ratio.MicroLED.)
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),
Due to the LCD layer that generates the desired high resolution images at flashing video speeds using very low power electronics in combination with LED based backlight technologies, LCD technology has become the dominant display technology for products such as televisions, desktop monitors, notebooks, tablets, smartphones and mobile phones. Although competing OLED technology is pushed to the market, such OLED displays do not feature the HDR capabilities like LCDs in combination with 2D LED backlight technologies have, reason why the annual market of such LCD-based products is still growing faster (in volume) than OLED-based products while the efficiency of LCDs (and products like portable computers, mobile phones and televisions) may even be further improved by preventing the light to be absorbed in the colour filters of the LCD.
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.
Displays having a passive-matrix structure are employing 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,
STN LCDs have to be continuously refreshed by alternating pulsed voltages of one polarity during one frame and pulses of opposite polarity during the next frame. Individual pixels are addressed by the corresponding row and column circuits. This type of display is called response times and poor contrast are typical of passive-matrix addressed LCDs with too many pixels and driven according to the "Alt & Pleshko" drive scheme. Welzen and de Vaan also invented a non RMS drive scheme enabling to drive STN displays with video rates and enabling to show smooth moving video images on an STN display.
Bistable LCDs do not require continuous refreshing. Rewriting is only required for picture information changes. In 1984 HA van Sprang and AJSM de Vaan invented an STN type display that could be operated in a bistable mode, enabling extremely high resolution images up to 4000 lines or more using only low voltages.
High-resolution color displays, such as modern LCD computer monitors and televisions, use an active-matrix structure. A matrix of thin-film transistors (TFTs) is added to the electrodes in contact with the LC layer. Each pixel has its own dedicated transistor, allowing each column line to access one pixel. When a row line is selected, all of the column lines are connected to a row of pixels and voltages corresponding to the picture information are driven onto all of the column lines. The row line is then deactivated and the next row line is selected. All of the row lines are selected in sequence during a refresh operation. Active-matrix addressed displays look brighter and sharper than passive-matrix addressed displays of the same size, and generally have quicker response times, producing much better images. Sharp produces bistable reflective LCDs with a 1-bit SRAM cell per pixel that only requires small amounts of power to maintain an image.
Segment LCDs can also have color by using Field Sequential Color (FSC LCD). This kind of displays have a high speed passive segment LCD panel with an RGB backlight. The backlight quickly changes color, making it appear white to the naked eye. The LCD panel is synchronized with the backlight. For example, to make a segment appear red, the segment is only turned ON when the backlight is red, and to make a segment appear magenta, the segment is turned ON when the backlight is blue, and it continues to be ON while the backlight becomes red, and it turns OFF when the backlight becomes green. To make a segment appear black, the segment is always turned ON. An FSC LCD divides a color image into 3 images (one Red, one Green and one Blue) and it displays them in order. Due to persistence of vision, the 3 monochromatic images appear as one color image. An FSC LCD needs an LCD panel with a refresh rate of 180 Hz, and the response time is reduced to just 5 milliseconds when compared with normal STN LCD panels which have a response time of 16 milliseconds.
Samsung introduced UFB (Ultra Fine & Bright) displays back in 2002, utilized the super-birefringent effect. It has the luminance, color gamut, and most of the contrast of a TFT-LCD, but only consumes as much power as an STN display, according to Samsung. It was being used in a variety of Samsung cellular-telephone models produced until late 2006, when Samsung stopped producing UFB displays. UFB displays were also used in certain models of LG mobile phones.
Twisted nematic displays contain liquid crystals that twist and untwist at varying degrees to allow light to pass through. When no voltage is applied to a TN liquid crystal cell, polarized light passes through the 90-degrees twisted LC layer. In proportion to the voltage applied, the liquid crystals untwist changing the polarization and blocking the light"s path. By properly adjusting the level of the voltage almost any gray level or transmission can be achieved.
In-plane switching is an LCD technology that aligns the liquid crystals in a plane parallel to the glass substrates. In this method, the electrical field is applied through opposite electrodes on the same glass substrate, so that the liquid crystals can be reoriented (switched) essentially in the same plane, although fringe fields inhibit a homogeneous reorientation. This requires two transistors for each pixel instead of the single transistor needed for a standard thin-film transistor (TFT) display. The IPS technology is used in everything from televisions, computer monitors, and even wearable devices. 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 2009, 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. Currently Panasonic is using an enhanced version eIPS for their large size LCD-TV products as well as Hewlett-Packard in its WebOS based TouchPad tablet and their Chromebook 11.
In 2015 LG Display announced the implementation of a new technology called M+ which is the addition of white subpixel along with the regular RGB dots in their IPS panel technology.
Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. This means that a 4K TV cannot display the full UHD TV standard. The media and internet users later called this "RGBW" TVs because of the white sub pixel. Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it became more popular in the TV market because the announced 4K UHD resolution but still being incapable of achieving true UHD resolution defined by the CTA as 3840x2160 active pixels with 8-bit color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.
In 2011, LG claimed the smartphone LG Optimus Black (IPS LCD (LCD NOVA)) has the brightness up to 700 nits, while the competitor has only IPS LCD with 518 nits and double an active-matrix OLED (AMOLED) display with 305 nits. LG also claimed the NOVA display to be 50 percent more efficient than regular LCDs and to consume only 50 percent of the power of AMOLED displays when producing white on screen.
This pixel-layout is found in S-IPS LCDs. A chevron shape is used to widen the viewing cone (range of viewing directions with good contrast and low color shift).
Vertical-alignment displays are a form of LCDs in which the liquid crystals naturally align vertically to the glass substrates. When no voltage is applied, the liquid crystals remain perpendicular to the substrate, creating a black display between crossed polarizers. When voltage is applied, the liquid crystals shift to a tilted position, allowing light to pass through and create a gray-scale display depending on the amount of tilt generated by the electric field. It has a deeper-black background, a higher contrast ratio, a wider viewing angle, and better image quality at extreme temperatures than traditional twisted-nematic displays.
Blue phase mode LCDs have been shown as engineering samples early in 2008, but they are not in mass-production. The physics of blue phase mode LCDs suggest that very short switching times (≈1 ms) can be achieved, so time sequential color control can possibly be realized and expensive color filters would be obsolete.
Some LCD panels have defective transistors, causing permanently lit or unlit pixels which are commonly referred to as stuck pixels or dead pixels respectively. Unlike integrated circuits (ICs), LCD panels with a few defective transistors are usually still usable. Manufacturers" policies for the acceptable number of defective pixels vary greatly. At one point, Samsung held a zero-tolerance policy for LCD monitors sold in Korea.ISO 13406-2 standard.
Dead pixel policies are often hotly debated between manufacturers and customers. To regulate the acceptability of defects and to protect the end user, ISO released the ISO 13406-2 standard,ISO 9241, specifically ISO-9241-302, 303, 305, 307:2008 pixel defects. However, not every LCD manufacturer conforms to the ISO standard and the ISO standard is quite often interpreted in different ways. LCD panels are more likely to have defects than most ICs due to their larger size. For example, a 300 mm SVGA LCD has 8 defects and a 150 mm wafer has only 3 defects. However, 134 of the 137 dies on the wafer will be acceptable, whereas rejection of the whole LCD panel would be a 0% yie