can lcd screen be repaired made in china
Mandy, ETS is obviously a company that you are connected to and this could easily be taken for spam. I think we can make an exception at this time since you are asking a good market research question that may be useful to many.
Having checked out your video, I personally will not use the aftermarket screen as a replacement for my X. It just doesn"t have what I expect for a $1000 USD phone. I recognize that $300 USD for a replacement is hefty but the aftermarket screen does not appear to have the quality that I would expect for my phone.
Broken screen replacement service is provided from thousands of repairs stores and phone parts wholesalers worldwide, iPhone of which are mostly engaged in. So how to purchase reliable LCD screens among so many quality grades from China suppliers? Let me firstly elaborate on the quality grades of the iPhone LCD digitizer assembly that most repair stores and traders used to replace the broken ones.
According to the investigation, 90% of the Chinese iPhone LCD screen suppliers are found selling third-party manufactured screens and seldom sell genuine original LCD screens. Therefore, if your phone screen is broken, there would be a high chance for your screen to be replaced with a non-original one. Why? Maybe the cost and quality are relatively competitive, so why not?
As known, Foxconn is authorized to assemble iPhone, so there are some original iPhone LCD screens leaked from the assemble factory. And there are brought out from the factory for replacement. However the price is definitely high and still, some people care more about the quality of the screen than how much they cost, so for this group of customers, the Original Quality of LCD digitizer assemblies are preferred.
For some LCD digitizers, the LCDs are still working while the front glasses are broken, which can be recycled. Some factories recycled these broken screens by removing the broken front glass and attach a new one, then the LCD digitizer assembly would be new again, which is what called refurbished. Brand new original LCD screens are limited, and the refurbished ones can replenish the shortage of the new original LCD digitizer assemblies, for their quality would be more stable than the third-party manufactured.
Some Chinese factories purchase the original single LCD display, not compete LCD screen from the original factory, and then attach high copy front glass, backlight, etc, materials into a complete LCD screen, which quality is not stable and the display color is slightly different from the ones with high copy backlight. Well, their price would be cheaper and loved by many repair shops and wholesalers.
Under the shortage of original LCD screens, many Chinese factories begin to produce the high copy LCD screen. The stock and supply are getting less and less since about 2015, which leads the price goes higher and higher. Therefore the Chinese manufacturer starts to produce LCD screens with high copy raw materials. With competitive prices and good quality that meet most iPhone users’ needs, they are also popular among many wholesalers and repair shops.
With the premium quality of LCD and OLED screens tested strictly, we’ve helped many clients enlarge their markets worldwide. If you wholesale the LCD digitizer assembly or retail them in your repair shop, more information and sample are supported for your reference, please do not hesitate to contact us or leave your comment to discuss more.
Alibaba.com offers 87,664 lcd screen repair products. such as machinery repair shops, manufacturing plant, and retail. You can also choose from 1 year, 6 months, and 1.5 years. As well as from provided. And whether lcd screen repair is white, black, or gray.
China, we’re told, can make anything. If you need some PCBs in a few weeks, there are a few factories in China that will do it. If you need a nuclear reactor, yep, there’s probably a factory in China that’ll do it because nuclear reactors are listed as one of the items facing new tariffs when imported into the United States. No, I am not kidding. What about LCDs? What about old-school character LCDs? Is it possible to find a factory in China that will make you the LCD you want? That’s what [Robert Baruch] will find out, because he’s repairing an old computer with new parts.
The object of this repair and restomod is a TRS-80 Pocket Computer (PC-1), otherwise known as the Sharp PC-1211. It looks like a calculator, but no, it’s a legitimate computer you can program in BASIC. [Robert] bought this computer for a bit more than $5 on eBay ‘for repair’, which means the zinc-air battery was dead, and unfortunately, the LCD was shot. The LCD technically works, but it just doesn’t look good. Sometime in the last thirty years, moisture got in between the layers of glass, polarizing film, and liquid crystal. This is not unique to [Robert]’s unit — a lot of these PC-1s have the same problem, many of these broken seals rendering the computers themselves useless.
This is an ancient computer, and replacements for this LCD are impossible to find, but because the Sharp PC-1211 is well documented, it is possible to find the datasheet for the original display. With that, it’s just a question of finding an LCD manufacturer that will do it. So far, the costs look good — $800 USD ($300 for tooling and 10 samples, $500 for another 200 LCDs) is what it’ll take to get a few units. [Robert] already has a few people interested in repairing their own Pocket Computers. You can follow the eevblog thread here, or check out the video below.
Since the iPhone 7/7 Plus has been released for quite a long time, finally the China made iPhone 7/7 Plus screen replacementscame out in the market. we’ve got some iPhone 7 series LCD screen replacements samples and done some tests on them, now let’s take a closer look at these new iPhone 7 series LCD screen replacements!(TianmaandLGsources for testing)
After installing all the sample screens to the iPhone 7/7 Plus rear housing assembly, we found that all the China made iPhone 7 series screen replacements are fitting well just like the original ones - the home button fits well, the screen assembly and the rear housing also fits well.
From the picture below, we can see that there is no difference between the China made iPhone 7 series display and the original ones, however, back to the rear side, we can easily figure out which one is which, cause the original one has Apple logo on it while the China made screen has none.
By comparing these two iPhone 7 screens, we can find that the screen flex cables are much different, there are extra IC on the China-Made iPhone 7 screen while the original one has none. And the original iPhone 7 series screen flex cable is integrated together while on the China-Made iPhone 7 series screen the touch function flex cable is soldered to the display and 3D touch flex cable.
Another difference between the original and China made iPhone 7 screen replacements is the exposed IC on the after-market iPhone screen, just like other China-Made iPhone 5 or 6 series screen replacement, which has more potential risk of electrostatic damage and more likely to get damaged and this problem needs to be improved.
During our test, we found that the display color between our after-market iPhone 7 screen and original screen seems a little different although they are not effecting the touch function. And to be honest, there may have some black dots on the screen because of impurities within the screen module when laminating the LCD and backlight together, without any doubt, this can be solved with technical improvement.
The screen touch sensitivity is another big concern for all of us, luckily, during our test, almost all home button and touch functionality on both iPhone 7 and 7 Plus works well, except one piece of iPhone 7, the 3D touch function is not acting so well on the central part of the screen.
The China-Made iPhone 7 series LCD screen assembly replacement still remains to be improved in quality and performance compared to the original ones, the exposed IC, heavier screen flex cable ribbon, and the screen color difference, the touch function stability, although the price is attractive. However, the China made iPhone 7 series screen replacement is under the improvement, and sooner or later their quality and performance can be quite close to original ones and acceptable, if you"re going to stock up some non-original iPhone 7 series LCD screen replacement, pay more attention and we’ll keep you updated with further information about after-market iPhone 7 series screen replacement!
“Original” screens are those containing LCDs manufactured for Apple. “Copy” screens are compatible replacements entirely designed and manufactured by third-party companies not associated with Apple.
LCD display panel can have poorer resolution (i.e. looks “coarser”), worse brightness, contrast and vibrancy and reduced refresh rate amongst other problems.
Changes in specification from original can result in battery and performance issues. Certain badly-engineered screens could even damage the backlight circuitry.
Customers who bring their iPhones to us for a screen repair are offered two choices of replacement- an original or a “copy” screen. The most common response is “Is there a difference- and which one would you recommend?”
Originals are those screens containing LCDs that were manufactured for Apple. So-called “copy” screens are compatible replacements, but designed and manufactured entirely independently by third-party companies, typically in China.
Our answer is simple- the original screen is the one we’d go for ourselves, every time. Some people think we make more money on them, but this isn’t the case. We recommend originals because they’re far higher quality and the price difference is fairly small.
We’d rather only fit original screens. The only reason we don’t is that many people will shop around and choose purely on price. As such, we need to offer the cheaper copy screens to remain competitive and avoid losing these customers. In some cases, they didn’t even know there was a difference in the first place- especially since it’s not in some shops’ interest to draw people’s attention to the issue!
This may well be the worst copy screen we’ve ever come across. As a result, the unfortunate customer has ended up paying twice to have their screen replaced- we’re sure that had they been properly informed, they would have chosen an original in the first place.
While the difference in price between copies and originals can vary across devices, it’s generally around £10 – £14 extra to have an original screen fitted. This really isn’t a lot considering the improved quality and reliability.
We compare our prices to our competitors- and we know that we come out of it favourably. While we have to offer copy screens to remain competitive, we always advise customers to go for the original.
When you’ve spent- directly or indirectly- several hundred pounds for an iPhone with a Retina display, it doesn’t make sense to replace it with a lower-quality screen that can make a £400 phone look like a £40 one! Not only that, but you’re likely to have fewer issues, and a longer-lasting screen.
There’s nothing stopping any random person without training or experience opening up a smartphone repair shop. As a result, the industry is full of companies with little skill or experience who are only interested in getting hold of your money and installing the cheapest parts they can find.
Many- if not most- don’t even acknowledge the existence of copy screens, let alone explain the difference to the customer. Hardly in their interest to do so if they only fit cheap, low-quality copies. Some of them can hardly be blamed- they know so little, they’re not even clear on the differences between OEM, non-OEM and copy displays themselves! Others can be more deliberately misleading… and some outright lie.
Generally, these shops are looking for the cheapest price on replacement screens.. When offered a copy at a half or a third of a price of the original, they’re going to go for that. That might be fine if they offered the customer a cheaper price- what we disagree with is selling “supermarket beans” (i.e. the copy screens) at “Heinz beans” prices!
Heading towards the “blatantly fraudulent”, we’re aware of companies that shamelessly fit copy screens while claiming them to be original. Worse, they’ll take your broken original screen and sell that to a recycler for more than they paid for your copy!
Apple tightened up their supply chain around 2015, which reduced the number of screens available for repairs and increased their price dramatically. A lot of companies went bankrupt, and Chinese manufacturers responded by making their own “copy” screens from scratch. At first, these weren’t much cheaper than the Apple ones, but the price soon fell.
We should be clear that- despite the name- “copy” screens aren’t direct copies of the Apple originals. Rather, they’re compatible replacements that have been designed from scratch and- as a result- vary in some respects that have an effect on usability and quality.
One of the most important differences between an original and a “copy” screen is how the digitizer (touch sensor) is designed. Apple has it manufactured as part of the LCD itself, whereas the copies have it on the glass.
Although there are only a small number of manufacturers of the bare LCDs themselves, these are then bought by countless other companies who add the remaining components needed to turn these into a complete working screen. As a result, you could easily end up with an LCD from the best “copy” manufacturer, but the digitizer/touch (as part of the separately-manufactured glass) from the worst.
There are countless digitizers out there, and you can only take the supplier’s word that the quality is good. Many ship good ones at first, then switch to cheaper parts to make more profit. This is particularly bad with the iPhone 6S and 6S+, since Apple moved the chips responsible for touch processing onto the LCD itself. As a result, you’re not just getting a copy screen- you’re getting copy chips too.
The performance specification (power drain, etc.) of most copy screens isn’t identical to the originals. As a result, they can drain the battery more quickly and mislead the operating system which was optimised for the original screen design.
It’s even possible that this mismatch could damage your backlight. We do a lot of subcontracted repairs for less-experienced shops, and get backlight repairs in almost every day. We’ve had cases where we fixed the circuit, fitted the new copy screen to test it, and had it break the circuit again!
Copy screens can disrupt the touch ID fingerprint reader. With the 6S, 6S+, 7 and 7+, the home button- part of the 3D touch- is part of the screen assembly. Frequently the home button flexes on aftermarket designs don’t work properly and stop the touch ID working- annoying if you use it to unlock the phone or log in to your bank.
We’ve seen many lift away from the frame that holds them in place. This usually results in the flex cable getting torn, and the screen needing replacing. You don’t even need to have dropped the phone- this often happens through general everyday wear and tear.
That brings us to another major issue with the copies. When you drop an Apple original, the glass often breaks, but if the LCD itself is intact, you can continue to use it until it’s fixed. With the copies, the touch/digitizer is on the glass and stops working when that’s broken. Even worse, the LCD itself is more likely to break due to the thinner and more fragile glass.
We’re not convinced this will happen, since Apple recently changed their repair policy to accept iPhones with third-party screens. However, it is possible that copy screens could be stopped from working via an iOS update, since those make a number of security checks.
The rumor that the China made iPhone LCDs can’t survive the upcoming iOS updates existed for quite a long time which aroused panic among repair shops. Many repair shops who want to use/have already used these screens to compete with authorized repair are wondering, will Apple brick these iPhone to kill the third party repair? We ETrade Supply don’t think so and here is why:
Do you still remember that users sued Apple for bricked iPhone due to "error 53"? The situation is almost the same except only few people have let their home button be replaced by third party repair shops. How many China made iPhone LCDs have been sold? We don’t have the exact number. However, from what we know, the number should be over 1 million pieces at least. Will Apple brick millions of iPhones just to kill third party repairs?
Same rumors for the 4/4S screen before. The OEM LCDs for 4/4s died out for quite a long time, all screens supplied were China copy one since 2 years ago. Not a case of bricked phone/unusable have showed for the updating to the new iOS system.
The most possible reason that this rumor has been created—is just to cut the price of the China copy iPhone LCD and more possibly-- the demand for it.
A week before the Apple event in March 2016, the rumor was “China made iPhone LCDs can’t survive in the coming iOS 9.3 updates”, the price of these LCDs dropped significantly and everyone was holding their orders, waiting to see the result. Within one week, the price has dropped around $10/pc. After people found out that they did survive, the price increased again and here came the rumor “the China made iPhone LCDs won’t survive the iOS 10 updates”.
Since last June, more and more repair shops have accepted the China made iPhone LCDs because less OEM screens are supplied. A large certain amount of demand of OEM iPhone screens has been moved the China made ones. The rumor that “the China made iPhone LCDs won’t survive the newest iOS updates” will sure bring some demand back to those crappy OEM screen which have been used for quite a long time/ refurbished for multiple times.
The rumor is “ALL the China made iPhone LCDs won’t survive the iOS 10 updates”, not only for 5 series. As we all know, there are already China Made 6 screens in the market. Those who stocked large amount OEM 6 screens will be happy to see people still paying high price for the OEM 6 screens for quite a long time.
The supply chain of cell phone replacement parts is sophisticated, unclear and without any standards, which make it look more like gambling. Find a reliable long-term relationship partner who can grow with you is the key to success for repair shops. If you have any questions regarding the China made LCDs, please leave your comment below!
Use our “Get an Estimate” tool to review potential costs if you get service directly from Apple. The prices shown here are only for screen repair. If your iPhone needs other service, you’ll pay additional costs.
If you go to another service provider, they can set their own fees, so ask them for an estimate. For service covered by AppleCare+, your fee per incident will be the same regardless of which service provider you choose.
Your country or region offers AppleCare+ for this product. Screen repair (front) is eligible for coverage with a fee by using an incident of accidental damage from handling that comes with your AppleCare+ plan.
Replacement equipment that Apple provides as part of the repair or replacement service may contain new or previously used genuine Apple parts that have been tested and pass Apple functional requirements.
We mainly provide iPhone, iPad, Samsung, etc famous brand parts, covering the LCD displays, touch screen digitizers, glass lenses, back cover, flex cable, vibrator, speaker, back and front cameras, accessories, etc.
Chemicals leaking from millions of computer screens in homes, offices and schools could damage human health, according to research by Chinese scientists.
Chemistry professor Su Guanyong and colleagues at Nanjing University of Science and Technology in eastern Jiangsu province studied more than 360 types of chemicals used in computer and mobile phone screens and found that 87 of them could be a danger if they got into the environment.
Some chemicals in liquid crystal displays (LCDs) could alter genes, they said. Animal cells mutated unexpectedly if exposed, and preliminary results of their ongoing study published in Proceedings of the National Academy of Sciences on Monday showed that one of the most polluted places was the home.
Researchers said about a quarter of the chemicals from screens they tested might be pollutants. Photo: Getty alt=Researchers said about a quarter of the chemicals from screens they tested might be pollutants. Photo: Getty
Studies found that excessive radiation from screens could speed up the ageing of skin and blue light from diodes could harm the retina of the eye. "But nobody has looked beyond the brightness to unveil the dark secrets behind," Su said.
Over the years, screen panel manufacturers have pushed LCD technology to higher resolutions and faster refreshing rates, but the chemical composition of the liquid crystal that fills their screens has hardly changed.
Su and colleagues produced a list of chemicals used by manufacturers and found that 87 " about a quarter of the substances tested " might be "persisting organic pollutants" that were not only harmful to health, but their composition meant they would take years or sometimes decades to decompose. The exact effect of these chemicals was unknown.
Smartphones mean booming demand for components such as screens. Photo: Ben Sin alt=Smartphones mean booming demand for components such as screens. Photo: Ben Sin
They exposed embryonic chicken cells to liquid crystal taken from the screens and compared them to cells grown in normal conditions. They found genetic changes that suggested the exposed cells had mutated.
"Our laboratory has tested a large number of toxic substances. This [effect] is similar to the exposure of other known persistent organic pollutants," Su said.
The Nanjing team was baffled by the amount of liquid crystal in the air. They knew screens were made in dust-free factories and sealed, but their surveys of hotels, school buildings, canteens, dormitories, electronic product repair centres, homes and laboratories revealed surprising results.
Scientists say cracked screens and leaking chemicals are a worldwide problem. Photo: Shutterstock alt=Scientists say cracked screens and leaking chemicals are a worldwide problem. Photo: Shutterstock
The lowest levels were found in a canteen, a dormitory and classrooms. Su said they were not sure where the drifting liquid crystals came from. Some screens might have been cracked or broken, he said. If a screen was left on for a long time, heat and radiation might cause liquid crystal to evaporate.
There was no solution to the problem at this stage, the researchers said. To push the government for more strict regulations meant that the scientific community had to come up with more evidence and a better understanding of the problem.
"Electric device recycling plants could be a major source of emissions, with broken screens dumped everywhere and little protection. This practice must stop," he said.
We must verify whether the problem is the display screen of the laptop, video card (GPU), or video settings on the computer. A straightforward way to identify this is to connect the laptop to an external monitor or TV.
If the issue persists on the external monitor, it may be an issue with the video card (GPU) or video settings and not the laptop LCD panel. Go to verify display or video issues in Windows Safe Mode. Otherwise, go to the next step.
Performance issues may occur if there is any damage to the LCD screen. The display may stop working, work intermittently, flicker, display horizontal or vertical lines, and so on, if there is damage to the display screen.
Dell laptops have integrated diagnostic tools that can determine if the screen abnormality is an inherent problem with the LCD screen of the Dell laptop or with the video card (GPU) and computer settings.
When you notice screen abnormalities like flickering, distortion, clarity issues, fuzzy or blurry images, horizontal or vertical lines, color fade, running a diagnostic test on the LCD helps identify if the issue is with the LCD panel.
Press and hold the D key and turn on the computer to enter the LCD built-in self-test (BIST) mode. Continue to hold the D key until you see the entire screen change colors.
If you do not detect any screen abnormalities in the integrated self-test mode, the LCD panel of the laptop is functioning properly. Go to the Update the video card (GPU) driver, monitor driver, and BIOS section.
If you notice any abnormalities in the LCD built-in self-test mode, contact Dell Technical Support to learn more about repair options that are available in your region.
Windows Safe Mode does not load any drivers, startup applications, third-party services. This will help us identify if the issue is related to the operating system, video settings, device drivers, or third-party software. To learn how to boot your computer into Safe Mode, see the Dell knowledge base article below based on the operating system that is installed on the computer:
Windows updates can support your Windows operating system in many ways. Windows updates can solve specific problems, provide security patches and protection from malicious attacks, or even add new features to the operating system.
Display settings like brightness, refresh rate, resolution, and power management may affect the performance of the LCD screen on your Dell laptop. Changing or adjusting the display settings can help resolve several types of video issues.
If you find that the Dell laptop is unresponsive to touch, touch stops working entirely, or other touch-related issues, you can try some common troubleshooting steps to help fix the touch-related issue.
Stress Test can thoroughly diagnose the video card (GPU) on your computer and report any potential hardware problem. Running a stress test on your computer can verify if the hardware components are stable and thus reliable.
System Restore is an integrated Windows tool that is designed to protect and repair the operating system. When something goes wrong with your computer, System Restore must be used before you try to restore the operating system to factory default settings.
If the diagnostic tests on the LCD panel and the video card (GPU) passed, it is most definitely an issue that is related to software that is installed on the computer. If the above troubleshooting steps did not resolve the issue, you may try to restore the computer to factory default settings as a last resort.
Dell computers are built with a small amount of hard disk space that is reserved for reinstalling the operating system. This method is the easiest way to restore the computer to factory condition. The restoration process deletes all user data from the computer, so be sure to back up all your files before starting this process.
After seeing a growing demand, Machoule, a native of Port-au-Prince and a Lely High School graduate, taught himself the complicated and often poorly replicated process of refurbishing valuable LCD screens.
David Albers/Naples Daily News (2) Refurbtech technician Henderson Cius, left, and CEO Wendel Machoule, center, complete an order of refurbished iPhone LCD screens for client Andy Gillani, right, in the workshop of the Golden Gate business on Friday.
A collection of LCD screen await new frames, polarizing filters and glass after having broken glass removed at Refurbtech, a Golden Gate cellphone and tablet part refurbishing business and repair shop. (David Albers/Staff)
David Albers/NAPLES DAILY NEWS Refurbtech technician Henderson Cius tests the functionality of an LCD screen he was refurbishing April 7 in the business"s workshop in Golden Gate.
After building an online business refurbishing smartphone LCD screens, local entrepreneur Machoule, 30, recently opened a storefront in Golden Gate offering complete cellphone and tablet repair. After two months, he already is looking to expand.
What he found was that with the explosion of smartphone sales and their subsequent need for repair, one of the most expensive parts, the LCD screen, could be salvaged.
The LCD screens function under a layer of glass, a polarizing filter and a frame. A shattered screen from a dropped phone usually means only the glass layer has cracked while the valuable LCD still functions.
Machoule said he always has been business-minded and that he realized there was a market for refurbishing LCD screens because of the demand for replacements among the repair shops springing up everywhere.
Machoule bought broken screens online and researched the process. He purchased manufacturing machinery from China and translated instructions using Google Translate.
Machoule said he got the process down working out of his garage and building a business through Craigslist and eBay buying broken LCD screens, refurbishing and reselling them.
"I put my services on eBay to repair LCDs or entire phones. Then I started getting a lot of orders. I stopped needing to buy the broken ones," he said.
In a nutshell, the process uses heat and a thin wire to remove the frame, broken glass and polarizing filter from the LCD. The remaining glue is removed with a solvent.
A device is connected to the LCD to boot up several images to test whether it"s working. Lastly, new glass, a polarizing filter and a phone model-specific frame is fused onto the LCD, using machinery to seal it and remove air bubbles with vacuum pressure.
Machoule said the cost of repair fluctuates with the phone model and damage but that an average repair would be about $80 for the most common repairs of cracked screens or battery replacement.
As both a repair shop and a parts refurbishing company, Machoule said he can double his profits, as opposed to simply replacing parts like most repair shops.
Andy Gillani owns four repair shops between Naples and Tampa and uses Refurbtech to refurbish his LCD screens. Gillani said he could buy aftermarket parts from China but that the quality isn"t the same as having Refurbtech refurbishing the OEM part.
"He just changes the glass, so everything stays original. When you buy aftermarket parts, the Chinese LCD is made by LG, not by Apple. That makes a difference," Gillani said.
Dario Rubio owns a cellphone repair shop in Fort Myers. He has iCracked technician certification where he can buy parts, but he said he can greatly improve his bottom line by using refurbished parts from Refurbtech. He said he also can turn around repairs much faster by using parts refurbished locally, as opposed to national or international refurbishing companies.
"You have to send a message and wait a week for someone to answer, and then it is another week for someone to replace the screen for you. We can just come here and tell him you need to get it done, and that"s it," Rubio said.
"There are a lot of people that are doing it, but it is difficult to get a good refurbish. (Refurbtech) does a good job. Everybody cannot do the same thing. I know 10 people (doing it), and out of 10 people, only three do a good job," Gillani said.
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.
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.
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.
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.
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.
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, especially almost all LCD smartphone panels are IPS/FFS mode. IPS displays belong to the LCD panel family screen types. The other two types are VA and TN. Before LG Enhanced IPS was introduced in 2001 by Hitachi as 17" monitor in Market, the additional transistors resulted in blocking more transmission area, thus requiring a brighter backlight and consuming more power, making this type of display less desirable for notebook computers. Panasonic Himeji G8.5 was using an enhanced version of IPS, also LGD in Korea, then currently the world biggest LCD panel manufacture BOE in China is also IPS/FFS mode TV panel.
Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. This means that a 4K TV cannot display the full UHD TV standard. The media and internet users later called this "RGBW" TVs because of the white sub pixel. Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it became more popular in the TV market because the announced 4K UHD resolution but still being incapable of achieving true UHD resolution defined by the CTA as 3840x2160 active pixels with 8-bit color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.
In 2011, LG claimed the smartphone LG Optimus Black (IPS LCD (LCD NOVA)) has the brightness up to 700 nits, while the competitor has only IPS LCD with 518 nits and double an active-matrix OLED (AMOLED) display with 305 nits. LG also claimed the NOVA display to be 50 percent more efficient than regular LCDs and to consume only 50 percent of the power of AMOLED displays when producing white on screen.
This pixel-layout is found in S-IPS LCDs. A chevron shape is used to widen the viewing cone (range of viewing directions with good contrast and low color shift).
Vertical-alignment displays are a form of LCDs in which the liquid crystals naturally align vertically to the glass substrates. When no voltage is applied, the liquid crystals remain perpendicular to the substrate, creating a black display between crossed polarizers. When voltage is applied, the liquid crystals shift to a tilted position, allowing light to pass through and create a gray-scale display depending on the amount of tilt generated by the electric field. It has a deeper-black background, a higher contrast ratio, a wider viewing angle, and better image quality at extreme temperatures than traditional twisted-nematic displays.
Blue phase mode LCDs have been shown as engineering samples early in 2008, but they are not in mass-production. The physics of blue phase mode LCDs suggest that very short switching times (≈1 ms) can be achieved, so time sequential color control can possibly be realized and expensive color filters would be obsolete.
Some LCD panels have defective transistors, causing permanently lit or unlit pixels which are commonly referred to as stuck pixels or dead pixels respectively. Unlike integrated circuits (ICs), LCD panels with a few defective transistors are usually still usable. Manufacturers" policies for the acceptable number of defective pixels vary greatly. At one point, Samsung held a zero-tolerance policy for LCD monitors sold in Korea.ISO 13406-2 standard.
Dead pixel policies are often hotly debated between manufacturers and customers. To regulate the acceptability of defects and to protect the end user, ISO released the ISO 13406-2 standard,ISO 9241, specifically ISO-9241-302, 303, 305, 307:2008 pixel defects. However, not every LCD manufacturer conforms to the ISO standard and the ISO standard is quite often interpreted in different ways. LCD panels are more likely to have defects than most ICs due to their larger size. For example, a 300 mm SVGA LCD has 8 defects and a 150 mm wafer has only 3 defects. However, 134 of the 137 dies on the wafer will be acceptable, whereas rejection of the whole LCD panel would be a 0% yield. In recent years, quality control has been improved. An SVGA L