lcd panel taking advantage of fluorescent lamp in stock
The main functionality of the Basic Input/Output System (BIOS) is to perform the initial hardware checks after the computer is powered on and start up the operating system.
Which of the acronyms listed below refers to a series of basic hardware diagnostic tests performed by the startup BIOS after the computer is powered on?
After replacing a modular hardware component inside computer case, the updated information about specific parameters of the new device can be stored in: (Select 2 answers)
After completing the initial diagnostics and assigning system resources, the startup BIOS program checks for information about secondary storage devices that might contain the OS. The list of devices and the order in which they should be checked can be found and arranged in the CMOS setup utility, and this option is commonly referred to as:
After launching Windows Virtual PC application technician receives error message stating that the Hardware-Assisted Virtualization (HAV) feature is not enabled on the computer. Which of the following steps might help in fixing this problem?
It is imperative to discuss the importance of checking for grounding of electrical appliances and other equipment. The nurse should provide examples of comm...
The purposed network architecture will consist of four deployable tough boxed server stack’s which will contain two Dell 1130 1U Rugged Dart Frogs server bla...
The fact that the electrical grid provides employees access to stay associated with one another, regardless of their location in the world, is an incredible ...
Edison originated the first electric grid and ever since, the electric grid has been rapidly expanding, spreading to millions of cities across the globe. Not...
The advance in technology implies incrementation in the number of devices, machines as well as systems which, require electrical energy to operate. Therefore,
When it comes todisplay technologies such asprojectorsand panels, factors such as resolution and refresh rate are often discussed. But the underlying technology is equally, if not more, important. There are tons of different types of screens, from OLED and LED to TN, VA, and IPS. Learn about the various monitor and television types, from operation to pros and cons!
The most common form of monitor or TV on the market is LCD or Liquid Crystal Display. As the name suggests, LCDs use liquid crystals that alter the light to generate a specific colour. So some form of backlighting is necessary. Often, it’s LED lighting. But there are multiple forms of backlighting.
LCDs have utilized CCFLs or cold cathode fluorescent lamps. An LCD panel lit with CCFL backlighting benefits from extremely uniform illumination for a pretty even level of brightness across the entire screen. However, this comes at the expense of picture quality. Unlike an LED TV, cold cathode fluorescent lamp LCD monitors lack dimming capabilities. Since the brightness level is even throughout the entire array, a darker portion of scenes might look overly lit or washed out. While that might not be as obvious in a room filled with ambient light, under ideal movie-watching conditions, or in a dark room, it’s noticeable. LED TVs have mostly replaced CCFL.
An LCD panel is transmissive rather than emissive. Composition depends on the specific form of LCD being used, but generally, pixels are made up of subpixel layers that comprise the RGB (red-green-blue) colour spectrum and control the light that passes through. A backlight is needed, and it’s usually LED for modern monitors.
Please note that some of the mentioned types may be considered a sub-category of LCD TVs; therefore, some of the names may vary depending on the manufacturer and the market.
1)Film layer that polarizes light entering2)glass substrate that dictates the dark shapes when the LCD screen is on3)Liquid crystal layer4)glass substrate that lines up with the horizontal filter5)Horizontal film filter letting light through or blocking it6)Reflective surface transmitting an image to the viewer
While many newer TVs and monitors are marketed as LED TVs, it’s sort of the same as an LCD TV. Whereas LCD refers to a display type, LED points to the backlighting in liquid crystal display instead. As such, LED TV is a subset of LCD. Rather than CCFLs, LEDs are light-emitting diodes or semiconductor light sources which generate light when a current passes through.
LED TVs boast several different benefits. Physically, LED television tends to be slimmer than CCFL-based LCD panels, and viewing angles are generally better than on non-LED LCD monitors. So if you’re at an angle, the picture remains relatively clear nonetheless. LEDs are alsoextremely long-lasting as well as more energy-efficient. As such, you can expect a lengthy lifespan and low power draw. Chances are you’ll upgrade to a new telly, or an internal part will go out far before any LEDs cease functioning.
Please note that some of the mentioned types may be considered a sub-category of LED TVs; therefore, some of the names may vary depending on the manufacturer and the market.
Further segmenting LED TVs down, you"ll find TN panels. A TN or twisted nematic display is a type of LED TV that offers a low-cost solution with a low response time and low input lag.
These displays are known for their high refresh rates, ranging from 100Hz to 144Hz or higher. As a result, many monitors marketed towards gamers feature TN technology. The fast response time and low input lag make them ideal for fast-paced action and gaming. However, TN panels have some limitations.
They suffer from inferior colour reproduction, meaning that the colours they display may be less accurate and vibrant than other technologies. Additionally, they have poor viewing angles, meaning the picture quality can degrade when viewed from certain angles. This is due to the way the liquid crystal molecules point at the viewer and the orientation of the light polarizers at 90-degree angles.
Overall, while TN panels are an affordable and fast option, they may not be the best choice for those looking for accurate colour reproduction and wide viewing angles.
Like TN, IPS or In-plane Switching displays are a subset of LED panels. IPS monitors tend to boast accurate colour reproduction and great viewing angles. Price is higher than on TN monitors, but in-plane switching TVs generally feature a better picture when compared with twisted nematic sets. Latency and response time can be higher on IPS monitors meaning not all are ideal for gaming.
An IPS display aligns liquid crystals in parallel for lush colours. Polarizing filters have transmission axes aligned in the same direction. Because the electrode alignment differs from TN panels, black levels, viewing angles, and colour accuracy is much better. TN liquid crystals are perpendicular.
A VA or vertical alignment monitor is a type of LED monitor that features excellent contrast ratios, colour reproduction, and viewing angles. This is achieved by using crystals that are perpendicular to the polarizers at right angles, similar to the technology used in TN monitors. VA monitors are known for their deep blacks and vibrant colours, making them popular for media consumption and gaming.
They also have better viewing angles than TN monitors, meaning that the picture quality remains consistent when viewed from different angles. However, the response time of a VA monitor is not as fast as that of a TN monitor, which can be a concern for those looking to use the monitor for fast-paced action or gaming.
The pricing of VA monitors varies, but they are typically more expensive than TN monitors and less costly than IPS or OLED monitors. Overall, VA monitors are an excellent option for those looking for a balance between good picture quality and affordability.
A quantum dot LED TV or QLED is yet another form of LED television. But it’s drastically different from other LED variants. Whereas most LED panels use a white backlight, quantum dot televisions opt for blue lights. In front of these blue LEDs sits a thin layer of quantum dots. These quantum dots in a screen glow at specific wavelengths of colour, either red, green, or blue, therefore comprising the entire RGB (red-green-blue) colour spectrum required to create a colour TV image.
Quantum Dot TV (QD-TV): A type of television that uses quantum dots, also known as semiconductor nanocrystals, to produce more accurate and vibrant colours.
Please note that some of the mentioned types may be considered a sub-category of Quantum Dot TVs; therefore, some of the names may vary depending on the manufacturer and the market. Also, it"s worth mentioning that not all brands use the same technology. Some are using QD films or QD-LEDs, others are using QD-OLEDs, and the list could go on.
An OLED or organic light-emitting diode display isn’t another variation of LED. OLEDs use negatively and positively charged ions for illuminating individual pixels. By contrast, LCD/LED TVs use a backlight that can make an unwanted glow. In OLED display, there are several layers, including a substrate, an anode, a hole injection layer, a hole transport layer, an emissive layer, a blocking layer, an electron transport layer, and a cathode. The emissive layer, comprised of an electroluminescent layer of film, is nestled between an electron-injecting cathode and an electron removal layer, the anode. OLEDs benefit from darker blacks and eschew any unwanted screen glow. Because OLED panels are made up of millions of individual subpixels, the pixels themselves emit light, and it’s, therefore, an emissive display as opposed to a transmissive technology like LCD/LED panels where a backlight is required behind the pixels themselves.
The image quality is top-notch. OLED TVs feature superb local dimming capabilities. The contrast ratio is unrivalled, even by the best of QLEDs, since pixels not used may be turned off. There’s no light bleed, black levels are incredible, excellent screen uniformity, and viewing angles don’t degrade the picture. Unfortunately, this comes at a cost. OLEDs are pricey, and the image isn’t as bright overall when compared to LED panels. For viewing in a darkened room, that’s fine, but ambient lighting isn’t ideal for OLED use.
Please note that OLED technology can be applied to various displays and devices, and the list mentioned above may not be exhaustive. Also, some types may be considered a sub-category of OLED.
As you can see, a wide variety of displays are available on the market today, each with their unique advantages and disadvantages. While many monitors and TVs are referred to by various names, such as LED, IPS, VA, TN, or QLED, many are variations of LCD panels. The specific technology used in a display, such as the colour of backlighting and the alignment of pixels, plays a major role in determining the overall picture quality.
When choosing the right type of monitor or display for your needs, it"s important to consider all the options available and weigh the pros and cons of each one. This can include things like resolution, refresh rate, response time, colour accuracy, and more subjective factors like overall picture quality and viewing angles.
LED fluorescent lamp is the newest product line in the fluorescent family and is considered to be the final replacement for traditional fluorescent lamp. It is made up of white LED chip modules. Provided with the advantages of long life-span, radiation-free, energy saving, environmental friendly and stroboflash-free, LED fluorescent lamp is superior to other kinds of lamps.
Besides, the installation of LED fluorescent lamp is quite easy. Just to replace the original fluorescent lamp with the new LED one, and to take out the starter. What’s more, the electricity saving efficiency can reach as high as 50% compared to ordinary fluorescent lamp and the life span is more than 10 times than that of ordinary one, almost totally free of maintenance. LED fluorescent lamp is adaptive to be used in offices, factories, marketplaces, schools and houses and so on indoor spaces.
Traditional fluorescent lamp contains large amount of mercury vapor which will do harm to the environment if the lamp is broken up and the vapor volatilize into the atmosphere. On the contrary, LED fluorescent lamp does not contain mercury or lead, doing no harm to the environment. So, LED products are recognized to be the green lighting lamps in the 21st century.
Compared to traditional lamps which will generate a large amount of heat, LED lamps can directly make electric energy into light energy, causing less heat and no waste of the energy.
LED lamp will not produce any noise, enabling it to be a good choice for illumination application in high precision electrical instrument. It is also fit to be used in occasions like libraries, offices and so on.
Traditional fluorescent lamp uses alternating current, which will generate 100-120 times of stroboflash per second. As to LED fluorescent lamp, it can directly switch the alternating current into direct current, without causing any flickering, helpful to protect the eyes.
Traditional lamps will generate ultraviolet radiation, thus will attract mosquitoes to fly around the lamps. LED lamp doesn’t have this disadvantage, thus the indoor space will become cleaner.
Traditional fluorescent lamp should recur to rectifier to release high voltage to get brighten up. If the voltage fell, the lamp will went out. However, LED lamps can be lighted within a certain voltage range (80V-245V) and its brightness can be adjusted.
The power consumption for LED fluorescent lamp is lower than 1/3 of the traditional lamp’s consumption, and the life span for it is 10 times longer than that of traditional one. So there is no need to change the lamp for a long period of time, reducing the manpower and other costs.
LED lamp body is made by epoxy resin instead of glasses like other traditional lamps. So it is more rigid and safe. Even if falling to the floor, LED lamp will not be broken easily. Users can set their heart at rest when using LED lamps.
LED-vs-LCD? Lately, choosing a TV has become like walking into a candy store. There are so many TV technology options to choose from, and each of them seems just as good.
Then there are the technical terms to deal with, such as LED TV, LCD TV, QLED TV, UHD TV, OLED TV, and more. You might feel like you need to be a tech pro just to watch your favourite TV show in the evening or enjoy a game with your friend.
Here at Dynamo LED, we offer both LED and LCD TVs, and we appreciate the benefits of both TVs. Be sure to check out our buying an LED Display guide for more info.
First, an important thing to understand is that the LED (Light Emitting Diode) monitor is an improvised version of the LCD (Liquid Crystal Display). This is why all LED monitor is LCD in nature, but not all LCDs are LED monitors.
LCD technology revolutionized monitors by using cold cathode fluorescent lamps for backlighting to create the picture displayed on the screen. A cold cathode fluorescent lamp (CCFL) is a tiny fluorescent bulb. In the context of this article, LCDs refer to this traditional type of CCFL LCD TVs.
LED monitors took the old technology a step further by replacing the fluorescent bulbs with LED backlight technology. And OLED (organic light-emitting diode) technology improves it even further by eliminating the need for backlighting.
This turns a single monitor into a modular assortment of countless light-emitting diodes. Additionally, this expands how big the monitor can be without blowing up the cost exponentially.
The quality of direct-view LED screens is measured by pixel pitch. The pixel pitch is the distance between two adjacent LEDs on the display. The smaller the pixel pitch, the better the quality of the image.
Since LEDs replace fluorescent bulbs with light-emitting diodes, LED TVs are more energy-efficient than LCDs. A 32-inch LED TV screen consumes 10 watts less power than the same size LCD screen. The difference in power consumption increases as the size of the display increases.
Light-emitting diodes are considerably smaller than fluorescent lamps used in LCD monitors. Fluorescent lamps have a considerable thickness, but the thickness of diodes is next to none. Moreover, countless diodes are assembled in the same plane, so the thickness of the array isn’t increased no matter how many diodes are present.
Edge-lit LEDs have a slight drawback in viewing angle compared to LCDs, because of the position of the light source. However, direct-view LEDs offer a better angle for viewing than LCDs as the light source is evenly spread on the screen.
This is the time it takes to shift from one colour to another. Response times are generally measured in milliseconds (ms). The shorter the time to respond, the better the quality of the images produced.
Since LED displays use full-array LED backlighting rather than one big backlight, LED TVs offer significantly better contrast than LCDs. LCD backlighting technology only shows white and black, but LED backlighting can emit the entire RGB spectrum, thereby providing a deeper RGB contrast.
If you wonder which display will last longer, this debate is also won by LED displays. LED televisions have a longer lifespan of 100,000 hours on average, compared to 50,000 hours provided by LCD televisions.
An LED display provides the option to dim the backlight, along with other eye comfort features. Not only that, it provides a wider viewing angle without harming image quality. Therefore, an LED display is far better for your eyes than an LCD.
In an LED display, a lot of smaller diodes are used and if a diode is damaged, it can be replaced. In an LCD, you will need to replace the entire bulb in case of damage. Therefore, an LED display is easier and cheaper to maintain than an LCD.
Since LEDs are a better and newer technology, the price of an LED display is higher than an LCD. However, this is only when we are considering the purchase cost.
The picture quality of an LED display is far better than an LCD. Due to modular light-emitting diodes, an LED screen produces better control over the contrast, rendering a clear picture. Also, LED provides RGB contrast, which can show truer blacks and truer whites.
Not to forget, they provide a shorter response time as well. Both of these factors result inLED displays having a better picture quality compared to LCD displays.
Since LED displays are considerably thinner than LCDs, they weigh considerably less. On average, an LED screen weighs about half of an LCD screen of the same size.
As you might have noticed by now, LED wins the battle with LCD without any doubt. This is because LED displays have an advantage in all the factors that matter when considering a purchase, except price.
Even when you consider the price, you will find that while LED technology is costlier, it provides better value for money in the long run. This is because of the longer lifespan and easier maintenance of LED screens.
They are more attractive too. With the increasing shortage of space in new residential complexes, what better solution than an ultra-thin LED display giving a cinematic experience in the comfort of your home.
LED screens are the first choice among the public today, across generations. All are opting to switch to LED from LCD to make their lives more enjoyable and better.
In short, YES! LED lighting technology has come to a point where the efficiency makes it hard to justify keeping your old fluorescent lights or incandescent bulbs in place. Even though the initial replacement costs to choose LED tubes will be higher, you will see energy savings that will pay for those upfront costs within 2 years in most cases. New linear LED tube bulbs are simple plug-and-play and ballast compatible. You will simply need to remove your fluorescent bulb and plug in your LED light replacement.
LED replacement lamps are on average 30% more efficient than their fluorescent light counterparts. That means if you are spending $10,000 on your lighting energy costs per year, your bill will be reduced by $3,000 or more every year that you use the LED bulbs. Standard 4-foot T8 LED bulbs are available at as low as 12 watts of power consumption, while their fluorescent light counterparts will start at 25 watts.
One of the big reasons why LED tubes are more efficient is because it only emits light in one direction. The light emitting diodes (LEDs) are all arranged along the bottom of the lamp and send light downwards. Fluorescent lamps emit light in all directions, including up towards the ceiling where it is not needed.
Have you noticed that many LED fixtures have a lower lumen output than fluorescents? That is okay because LEDs are directional. They only emit light in the desired direction.
Some LED lamps are now rated to last up to 84,000 hours, while the average life of a fluorescent tube lamp is only 30,000 hours. That is over twice as long, so keep that in mind when you are calculating your purchase. The LED lamp is more expensive, but you will need to replace your fluorescent bulbs 2 or 3 times during the lifespan of an LED. Keep in mind the labor costs of replacing those fluorescent bulbs, particularly if you are lighting a large warehouse.
The ability to dim your lights increases their efficiency because you will only be using the wattage necessary for the amount of light that you require. Most fluorescent lights have two settings, ON and OFF. That means that even if you only need a little bit of light, you still need to operate at full power consumption. Some expensive fluorescent bulbs are dimmable with a special ballast, but at that point, your cost is comparable to an LED option.
One of the downfalls of fluorescent lighting is that each bulb contains mercury, which is harmful to the environment and must be disposed of properly. You can purchase special recycling kits to dispose of your fluorescent lamps properly, but add that to the cost of opting for fluorescent lighting over LED lights.
It used to be that LED bulbs were only available in cool color temperatures of 5000K and higher. That is not the case anymore, as LED bulbs are available between very warm(2700K) to extremely cool(5700K). Now you can use LED tube lamps in all sorts of applications from healthcare where you might want a cool color temperature, to your home where you might prefer a low and warm color temperature.
Have you ever picked up a fluorescent lamp that dropped on the ground? If you did it was probably with a broom and dustpan. Fluorescent tube lamps are notoriously fragile, but their LED counterparts are quite strong. They are built with durable, plastic housing that should even be able to withstand a drop from a low height.
Fluorescent lights put off a significant amount of heat. Your air conditioner will be battling that all day to keep your environment at an acceptable temperature. LEDs on the other hand put off virtually no heat. Beyond just the energy consumption of the bulbs, LEDs will help you cut down your air conditioning energy consumption.
A great way to improve efficiency in your warehouse or other space is to install occupancy sensors. This ensures that light will only be produced in areas where someone is present. Unfortunately, this can have a big impact on the life of your fluorescent lights. Each time you turn on a fluorescent bulb, a small amount of mercury vapor is burned off. Once that is diminished, the bulb will no longer work. On the other hand, the life of an LED bulb is not affected by the number of times it is turned on and off.
Many LED tubes are "plug and play", meaning you can just install them like you would a fluorescent bulb. For this to be true, look for bulbs that are "ballast-compatible" meaning that they can use the ballast already installed in your fluorescent fixture to power the LEDs.
The time has come for fluorescent lamps to step aside and make room for LED technology because LED lights are far more efficient and affordable than fluorescent lamps. Simply put, if you want to lower your energy demands while saving time and money on labor, switch your linear light fixtures to LED!
If you don"t have fluorescent fixtures and need to install new lighting, tube LEDs may not be the best choice. It is often more efficient to install a fixture with built-in LEDs that will not require bulbs. You can shop for those on ShineRetrofits.com here.
We have all heard about LED lights and witnessed the increasing popularity of LED lights in store displays and retail environments. But, do you know enough about the benefits of LED lighting to make a compelling argument for replacing the fluorescent lights in your retail environment or using LED lights in your next POP display? In today’s blog, we’ll review the high-level benefits of LED lights and discuss some of the problems with fluorescent lights.
Energy Efficiency– LED lights typically use about 80% less energy than normal incandescent bulbs. This energy efficiency is the reason LED light bulbs emit very little heat compared to incandescent bulbs which burn 98% of their energy as heat.
Long Life– High quality LED lights can last over 50,000 hours. Incandescent light bulbs last approximately 1,000 hours, and fluorescent lights are good for roughly 10,000 hours. So not only do LED lights consume less energy, but they last 5-50 times longer than alternative lighting fixtures for retail stores.
Durability– LED lights have no fragile filament and no fragile tube so they are less easily damaged. They are resistant to heat, cold, and shock. The durability advantage is especially important in POP displays that often need to stand up to shopper and shipping abuse. The display case shown below contains fluorescent lights which will have a predictably short life span.
Color Uniformity– LED lights offer color uniformity as compared to fluorescent lights which frequently present uneven color. Uniform color is essential in presenting merchandise in the most attractive way possible. Uneven color can compromise merchandising objectives, particularly in large displays cases like the one shown below.
Even higher end products like those shown below which use fluorescent lights suffer from uneven color (not to mention the shorter life span of the lights).
Furthermore, LED lighting offers a wide range of color options and provides significantly more control over the lighting environment. For example, warm white LEDs range from 2000K-3500K. Natural white LEDs range from 3600K-5000K. And, cool white LEDs range from 5100K-20,000K.
Easy Installation– LED lights are extremely easy to install and often come with plug and play components. The light box shown below is powered by LED light modules and is a snap to install.
Aside from the above benefits, LED lights are very versatile and can be used in a wide range of point-of-purchase displays and retail store fixtures. The flat display and the pedestal display shown below are just a couple examples of how ordinary displays can become extraordinary through illumination using interior LED bars.
Jim Hollen is the owner and President of RICH LTD. (www.richltd.com), a 35+ year-old California-based point-of-purchase display, retail store fixture, and merchandising solutions firm which has been named among the Top 50 U.S. POP display companies for 9 consecutive years. A former management consultant with McKinsey & Co. and graduate of Stanford Business School, Jim has served more than 3000 brands and retailers over more than 20 years and has authored nearly 500 blogs and e-Books on a wide range of topics related to POP displays, store fixtures, and retail merchandising.
Jim has been to China more than 50 times and has worked directly with more than 30 factories in Asia across a broad range of material categories, including metal, wood, acrylic, injection molded and vacuum formed plastic, corrugated, glass, LED lighting, digital media player, and more. He also oversees RICH LTD.’s domestic manufacturing operation and has experience manufacturing, sourcing, and importing from numerous Asian countries as well as Vietnam and Mexico.
LCD Lighting manufactures miniature backlight lamps (CCFL) for liquid crystal displays (LCD) in laptop computer screens. Most computer screens are lit with built-in fluorescent tubes above, beside and sometimes behind the LCD. A white diffusion panel behind the LCD redirects and scatters the light evenly to ensure a uniform display, which is known as a backlight.
In general, miniature lamps are multi-bend in shape and are 2mm to 18mm in outside diameter (O.D.). LCD Lighting miniature lamps can replace multiple lamp designs with more efficient, single-lamp systems. These single-lamp systems provide a number of important benefits, including simplified wiring harnesses, reduced power requirements and enhanced durability.
LCDL can work with OEMs to make connections for their specific applications. Please visit or Lamp Sub-Assembly page for more information about our value-added solutions.
In order to access the backlight lamp leads, the rubber caps from both side of the lamp need to be removed. Wear rubber gloves to avoid touching the backlight lamp with bare fingers.
Plasma screens contain tiny pockets of gas that get excited when voltage is applied to them, turning them into a state of plasma. In that state, the voltage then strikes electrons of mercury, turning them into ultraviolet (UV) light, which isn"t visible to the human eye. The UV light then passes through phosphor cells; each pixel contains red, green, and blue phosphor cells. Thanks to these phosphor cells, the TV can turn the UV light into colors that are visible on the light spectrum. Essentially, plasma TVs don"t require a light, and each pixel is self-emissive, so how one pixel displays itself is independent of the next pixel.
Since each pixel emits its own light, blacks are really deep. When the television wants to display black, it simply emits no light at all for the selected pixels. However, these aren"t perfect blacks because each pixel retains a bit of voltage, leaving a bit of light to pass through. Each pixel emits light in all directions, creating wide viewing angles, so the image remains accurate when viewing from the side.
The pixels aren"t excited continuously, but in short pulses, and some plasma TVs can pulse up to 600 times every second. The naked eye perceives this as flickering, and some people are very sensitive to this. There can also be some advantages to this; since each pixel holds a certain charge, it"s ready to turn on and off as needed, resulting in minimal motion blur. This means that fast-moving content, like in sports or video games, appears smooth.
One of the downsides of plasmas was how they suffered from occasional image retention if they displayed the same image for a long period. So if you watched the news for about an hour, with all of its static displays, then switch channels, you"d still see the outline of the static elements. Eventually, they disappeared, but it could have been particularly annoying. Also, after several years in use, plasmas suffered from permanent burn-in. This happened when the phosphor cells simply stayed stuck in one color and couldn"t display any colors. Unfortunately, there was no way to avoid eventual burn-in, and almost every plasma TV suffered from it.
OLED TVs have similar characteristics to plasmas with their infinite contrast ratio, wide viewing angles, near-instant response time, and to a lesser extent, the risk of permanent burn-in. Since 2012, they"ve replaced plasma as a competitor to LCD TVs, and to learn more about OLEDs and how they differ from LCD TVs, see here.
An LCD screen is composed of two parts: the actual liquid crystal display and a light source at the back of the screen (called backlight). A light diffuser is placed between the backlight and the LCD screen to make the source of light uniform across the screen.
The LCD panel doesn"t emit light by itself, and this is why it needs a backlight; it only acts as a filter to block the light on a per-pixel basis. The backlight is always on, and the pixels in the display rotate to allow light through, creating the colors needed for the image. If the screen wants to display black, the LCD pixels rotate to try to block the light completely. If it wants to display white, it lets all light through. Since the display is only a filter, the blacks will not be as deep as with a plasma screen because an LCD panel will always let a small portion of light through.
There are different types of LCD panels, each with its unique characteristics. Vertical Alignment (VA) panels generally have a high contrast ratio and narrow viewing angles, while In-Plane Switching (IPS) panels have a low contrast ratio with wide viewing angles. You can read about their differences here.
By using a backlight, LCD TVs use much less power than plasmas, which you can read about here. Also, LCD TVs tend to get much brighter than plasmas, making them more suitable for well-lit rooms. There are two main types of backlights used in LCD screens: CCFL and LEDs.
When someone refers to an LCD TV, they usually mean a Cold-Cathode Fluorescent Lamp (CCFL) backlit LCD screen. The first LCD TVs were lit by CCFLs, but they"re extremely rare as of the start of the 2020s. The backlight is a series of light tubes placed behind the screen. These tubes are very similar to fluorescent lamps used in buildings but smaller.
CCFL-backlit LCD TVs were eventually replaced by LED TVs because they cost less, were made thinner, and required less power. Also, LED TVs have more control over their backlight, resulting in vivid colors and better picture quality.
An LED (Light-Emitting Diode) screen is an LCD screen, but instead of having a normal CCFL backlight, it uses LEDs as the source of light behind the screen. Companies label their TVs as LED, even though they"re technically LCD; it can be confusing at times, but if you see an LED TV, you know it has an LCD panel. These TVs are more energy-efficient and a lot smaller than CCFLs, enabling a thinner television screen.
In a full-array LED screen, the LEDs are distributed evenly behind the entire screen. This produces a more uniform backlight and provides more effective use of local dimming, where it can turn off and dim complete zones of LEDs.
With an edge-lit LED screen, the LEDs are placed at the edges of the screen. Depending on the display, it can be all around the screen, on the left and right sides, or at the top and bottom. This allows the screen to be very thin.
Like the full-array method, the LEDs are directly behind the screen. However, there are very few of them, and they can"t be controlled separately to match the luminosity of the picture.
As TV companies attempt to improve their technology, a new type of LED backlighting has emerged: Mini LED. It uses the same traditional LED backlighting behind an LCD panel, except the LED lights are even smaller. This allows for more lights, creating a brighter image and more control over local dimming. Only a handful of Mini LED TVs were produced before 2021, but it now seems that manufacturers are starting to use the technology more often. The Samsung QN90A QLED is an example of a Mini LED TV.
Another technology, Micro LED, is only in its initial phases of development. This doesn"t even have an LCD panel as each LED pixel is self-emissive, similar to OLEDs, but without the burn-in risk. Currently, there aren"t any Micro LED TVs available at the consumer level; Samsung has produced large Micro LED TVs (over 100 inches), and they"re very expensive. However, we may begin to see Micro LED technology in the consumer TV market soon.
Plasma and LCD each present advantages and disadvantages when it comes to picture quality. Plasma TVs generally offer better contrast, wider viewing angles, and improved response times, while LCD TVs get much brighter and have better reflection handling. LCDs also cost less and can be much thinner, which are two of the main reasons why they took over the market share from plasmas in the mid-2000s. Plasma TVs are now extinct, and although OLEDs share many of the same characteristics, LED-backlight LCD TVs are now the norm, and it"s likely your next TV purchase will have an LCD panel.
To evaluate the performance of display devices, several metrics are commonly used, such as response time, CR, color gamut, panel flexibility, viewing angle, resolution density, peak brightness, lifetime, among others. Here we compare LCD and OLED devices based on these metrics one by one.
A fast response time helps to mitigate motion image blur and boost the optical efficiency, but this statement is only qualitatively correct. When quantifying the visual performance of a moving object, motion picture response time (MPRT) is more representative, and the following equation should be used
From Figure 5, we can gain several important physical insights: (1) Increasing the frame rate is a simple approach to suppress image motion blur, but its improvement gradually saturates. For example, if the LC response time is 10 ms, then increasing the frame rate from 30 to 60 fps would significantly reduce the MPRT. However, as the TFT frame rate continues to increase to 120 and 240 fps, then the improvement gradually saturates. (2) At a given frame rate, say 120 fps, as the LC response time decreases, the MPRT decreases almost linearly and then saturates. This means that the MPRT is mainly determined by the TFT frame rate once the LC response time is fast enough, i.e., τ≪Tf. Under such conditions, Equation (1) is reduced to MPRT≈0.8Tf. (3) When the LC response is <2 ms, its MPRT is comparable to that of an OLED at the same frame rate, e.g., 120 fps. Here we assume the OLED’s response time is 0.
The last finding is somehow counter to the intuition that a LCD should have a more severe motion picture image blur, as its response time is approximately 1000 × slower than that of an OLED (ms vs. μs). To validate this prediction, Chen et al.
If we want to further suppress image blur to an unnoticeable level (MPRT<2 ms), decreasing the duty ratio (for LCDs, this is the on-time ratio of the backlight, called scanning backlight or blinking backlight) is mostly adopted
As Figure 6 depicts, there are two types of surface reflections. The first one is from a direct light source, i.e., the sun or a light bulb, denoted as A1. Its reflection is fairly specular, and in practice, we can avoid this reflection (i.e., strong glare from direct sun) by simply adjusting the display position or viewing direction. However, the second reflection, denoted as A2, is quite difficult to avoid. It comes from an extended background light source, such as a clear sky or scattered ceiling light. In our analysis, we mainly focus on the second reflection (A2).
To investigate the ACR, we have to clarify the reflectance first. A large TV is often operated by remote control, so touchscreen functionality is not required. As a result, an anti-reflection coating is commonly adopted. Let us assume that the reflectance is 1.2% for both LCD and OLED TVs. For the peak brightness and CR, different TV makers have their own specifications. Here, without losing generality, let us use the following brands as examples for comparison: LCD peak brightness=1200 nits, LCD CR=5000:1 (Sony 75″ X940E LCD TV); OLED peak brightness=600 nits, and OLED CR=infinity (Sony 77″ A1E OLED TV). The obtained ACR for both LCD and OLED TVs is plotted in Figure 7a. As expected, OLEDs have a much higher ACR in the low illuminance region (dark room) but drop sharply as ambient light gets brighter. At 63 lux, OLEDs have the same ACR as LCDs. Beyond 63 lux, LCDs take over. In many countries, 60 lux is the typical lighting condition in a family living room. This implies that LCDs have a higher ACR when the ambient light is brighter than 60 lux, such as in office lighting (320–500 lux) and a living room with the window shades or curtain open. Please note that, in our simulation, we used the real peak brightness of LCDs (1200 nits) and OLEDs (600 nits). In most cases, the displayed contents could vary from black to white. If we consider a typical 50% average picture level (i.e., 600 nits for LCDs vs. 300 nits for OLEDs), then the crossover point drops to 31 lux (not shown here), and LCDs are even more favorable. This is because the on-state brightness plays an important role to the ACR, as Equation (2) shows.
Calculated ACR as a function of different ambient light conditions for LCD and OLED TVs. Here we assume that the LCD peak brightness is 1200 nits and OLED peak brightness is 600 nits, with a surface reflectance of 1.2% for both the LCD and OLED. (a) LCD CR: 5000:1, OLED CR: infinity; (b) LCD CR: 20 000:1, OLED CR: infinity.
Recently, an LCD panel with an in-cell polarizer was proposed to decouple the depolarization effect of the LC layer and color filtersFigure 7b. Now, the crossover point takes place at 16 lux, which continues to favor LCDs.
For mobile displays, such as smartphones, touch functionality is required. Thus the outer surface is often subject to fingerprints, grease and other contaminants. Therefore, only a simple grade AR coating is used, and the total surface reflectance amounts to ~4.4%. Let us use the FFS LCD as an example for comparison with an OLED. The following parameters are used in our simulations: the LCD peak brightness is 600 nits and CR is 2000:1, while the OLED peak brightness is 500 nits and CR is infinity. Figure 8a depicts the calculated results, where the intersection occurs at 107 lux, which corresponds to a very dark overcast day. If the newly proposed structure with an in-cell polarizer is used, the FFS LCD could attain a 3000:1 CRFigure 8b), corresponding to an office building hallway or restroom lighting. For reference, a typical office light is in the range of 320–500 luxFigure 8 depicts, OLEDs have a superior ACR under dark ambient conditions, but this advantage gradually diminishes as the ambient light increases. This was indeed experimentally confirmed by LG Display
Calculated ACR as a function of different ambient light conditions for LCD and OLED smartphones. Reflectance is assumed to be 4.4% for both LCD and OLED. (a) LCD CR: 2000:1, OLED CR: infinity; (b) LCD CR: 3000:1, OLED CR: infinity. (LCD peak brightness: 600 nits; OLED peak brightness: 500 nits).
For conventional LCDs employing a WLED backlight, the yellow spectrum generated by YAG (yttrium aluminum garnet) phosphor is too broad to become highly saturated RGB primary colors, as shown in Figure 9aTable 2. The first choice is the RG-phosphor-converted WLEDFigure 9b, the red and green emission spectra are well separated; still, the green spectrum (generated by β-sialon:Eu2+ phosphor) is fairly broad and red spectrum (generated by K2SiF6:Mn4+ (potassium silicofluoride, KSF) phosphor) is not deep enough, leading to 70%–80% Rec. 2020, depending on the color filters used.
Transmission spectra of color filters and emission spectra of (a) YAG WLED, (b) KSF WLED, (c) QDEF and (d) Vivid Color LED. KSF, potassium silicofluoride; QDEF, quantum dot enhancement film; WLED, white light-emitting diode; YAG, yttrium aluminum garnet.
A QD-enhanced backlight (e.g., quantum dot enhancement film, QDEF) offers another option for a wide color gamutFigure 9c), so that high purity RGB colors can be realized and a color gamut of ~90% Rec. 2020 can be achieved. One safety concern is that some high-performance QDs contain the heavy metal Cd. To be compatible with the restriction of hazardous substances, the maximum cadmium content should be under 100 ppm in any consumer electronic product
Recently, a new LED technology, called the Vivid Color LED, was demonstratedFigure 9d), which leads to an unprecedented color gamut (~98% Rec. 2020) together with specially designed color filters. Such a color gamut is comparable to that of laser-lit displays but without laser speckles. Moreover, the Vivid Color LED is heavy-metal free and shows good thermal stability. If the efficiency and cost can be further improved, it would be a perfect candidate for an LCD backlight.
A color filter array is another effective approach to enhance the color gamut of an OLED. For example, in 2017, AUO demonstrated a 5-inch top-emission OLED panel with 95% Rec. 2020. In this design, so-called symmetric panel stacking with a color filter is employed to generate purer RGB primary colors
As mentioned earlier, TFT LCDs are a fairly mature technology. They can be operated for >10 years without noticeable performance degradation. However, OLEDs are more sensitive to moisture and oxygen than LCDs. Thus their lifetime, especially for blue OLEDs, is still an issue. For mobile displays, this is not a critical issue because the expected usage of a smartphone is approximately 2–3 years. However, for large TVs, a lifetime of >30 000 h (>10 years) has become the normal expectation for consumers.
Here we focus on two types of lifetime: storage and operational. To enable a 10-year storage lifetime, according to the analysis−6 g (m2-day)−1 and 1 × 10−5 cm3 (m2-day)−1, respectively. To achieve these values, organic and/or inorganic thin films have been developed to effectively protect the OLED and lengthen its storage lifetime. Meanwhile, it is compatible to flexible substrates and favors a thinner display profile
The next type of lifetime is operational lifetime. Owing to material degradation, OLED luminance will decrease and voltage will increase after long-term drivingT50) can be as long as >80 000 h with a 1000 cd m−2 luminanceT50, half lifetime) with an initial luminance of 1000 nits. However, this is still ~20 × shorter than that of red and green phosphorescent OLEDs
To further enhance the lifetime of the blue OLED, the NTU group has developed new ETL and TTF-EML materials together with an optimized layer structure and double EML structureFigure 10a shows the luminance decay curves of such a blue OLED under different initial luminance values (5000, 10 000, and 15 000 nits). From Figure 10b, the estimated T50 at 1000 nits of this blue OLED is ~56 000 h (~6–7 years)
Power consumption is equally important as other metrics. For LCDs, power consumption consists of two parts: the backlight and driving electronics. The ratio between these two depends on the display size and resolution density. For a 55″ 4K LCD TV, the backlight occupies approximately 90% of the total power consumption. To make full use of the backlight, a dual brightness enhancement film is commonly embedded to recycle mismatched polarized light
The power efficiency of an OLED is generally limited by the extraction efficiency (ηext~20%). To improve the power efficiency, multiple approaches can be used, such as a microlens array, a corrugated structure with a high refractive index substrateFigure 11 shows the power efficiencies of white, green, red and blue phosphorescent as well as blue fluorescent/TTF OLEDs over time. For OLEDs with fluorescent emitters in the 1980s and 1990s, the power efficiency was limited by the IQE, typically <10 lm W−1(Refs. 41, 114, 115, 116, 117, 118). With the incorporation of phosphorescent emitters in the ~2000 s, the power efficiency was significantly improved owing to the materials and device engineering−1 was demonstrated in 2011 (Ref. 127), which showed a >100 × improvement compared with that of the basic two-layer device proposed in 1987 (1.5 lm W−1 in Ref. 41). A white OLED with a power efficiency >100 lm W−1 was also demonstrated, which was comparable to the power efficiency of a LCD backlight. For red and blue OLEDs, their power efficiencies are generally lower than that of the green OLED due to their lower photopic sensitivity function, and there is a tradeoff between color saturation and power efficiency. Note, we separated the performances of blue phosphorescent and fluorescent/TTF OLEDs. For the blue phosphorescent OLEDs, although the power efficiency can be as high as ~80 lm W−1, the operation lifetime is short and color is sky-blue. For display applications, the blue TTF OLED is the favored choice, with an acceptable lifetime and color but a much lower power efficiency (16 lm W−1) than its phosphorescent counterpartFigure 11 shows.
Power efficiency of white, red, green and phosphorescent blue and fluorescent/TTF blue OLEDs over time. Data are compiled from Refs. 41, 45, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133.
To compare the power consumption of LCDs and OLEDs with the same resolution density, the displayed contents should be considered as well. In general, OLEDs are more efficient than LCDs for displaying dark images because black pixels consume little power for an emissive display, while LCDs are more efficient than OLEDs at displaying bright images. Currently, a ~65% average picture level is the intersection point between RGB OLEDs and LCDs
In addition to the aforementioned six display metrics, other parameters are equally important. For example, high-resolution density has become a standard for all high-end display devices. Currently, LCD is taking the lead in consumer electronic products. Eight-hundred ppi or even >1000 ppi LCDs have already been demonstrated and commercialized, such as in the Sony 5.5″ 4k Smartphone Xperia Z5 Premium. The resolution of RGB OLEDs is limited by the physical dimension of the fine-pitch shadow mask. To compete with LCDs, most OLED displays use the PenTile RGB subpixel matrix scheme
The viewing angle is another important property that defines the viewing experience at large oblique angles, which is quite critical for multi-viewer applications. OLEDs are self-emissive and have an angular distribution that is much broader than that of LCDs. For instance, at a 30° viewing angle, the OLED brightness only decreases by 30%, whereas the LCD brightness decrease exceeds 50%. To widen an LCD’s viewing angle, three options can be used. (1) Remove the brightness-enhancement film in the backlight system. The tradeoff is decreased on-axis brightness
In addition to brightness, color, grayscale and the CR also vary with the viewing angle, known as color shift and gamma shift. In these aspects, LCDs and OLEDs have different mechanisms. For LCDs, they are induced by the anisotropic property of the LC material, which could be compensated for with uniaxial or biaxial films
Cost is another key factor for consumers. LCDs have been the topic of extensive investigation and investment, whereas OLED technology is emerging and its fabrication yield and capability are still far behind LCDs. As a result, the price of OLEDs is about twice as high as that of LCDs, especially for large displays. As more investment is made in OLEDs and more advanced fabrication technology is developed, such as ink-jet printing
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 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 cryst