lcd screen temperature range brands

Modern LCD screens have a great many uses. Not only are they now the system of choice for our home TVs and computers but their use in digital signage has made them a common sight in many shopping malls, airports and other locations with high quantities of people.

Even outdoor locations are no barrier to the use of modern LCD screens with outdoor digital signage a rising medium now seen in many town centers, car parks, front of stores and train station platforms.

All this out of home use means many screens operate in locations test the temperature limits of LCD displays. While waterproof screens and LCD enclosures designed for rugged applications provide the ability of the screen to operate-even in outdoor locations, one consideration often overlooked, is that of temperature.

LCD screens have a limited temperature range. Not only will the electronics inside an TV screen overheat and cause failure if the screen gets too hot, but the liquid crystal itself will begin to deteriorate under hot conditions.

The same is true of environments where temperatures fall below zero, causing a screen to stop functioning. A typical LCD TV has an operating range between 0°C (32°F) and 32°C (90°F).

Of course, many indoor and outdoor locations don’t suffer temperatures outside of this range, but many locations do and placing screens in these areas can prove challenging.

One of the problems with using a screen in hot locations is that the screen itself produces quite a bit of heat. When housed in an outdoor enclosure, the heat has to be continuously removed. While cooling fans combined with an air-vent normally carry out this task on an LCD, the need to prevent moisture from getting to the screen makes the task more complicated.

To get around this problem, specially shaped vents provide an exit for hot air while preventing rainfall and other moisture from getting in. In some locations where ambient temperatures are extremely high, screens need air conditioning to ensure they don’t exceed the maximum operating temperature.

In cold climates the opposite problem occurs. The need to keep heat in often requires insulation of the screen enclosure. Often this can trap enough of the heat generated by the screen itself to keep the internal temperature above minimum, but in some locations, even this isn’t enough. Heaters, controlled by thermostats provide extra heat in these circumstances, which enables the use of LCD displays in extremely cold locations such as ski-resorts and in Arctic regions.

Liquid crystal displays (LCD) have become an essential component to the industry of display technology. Involved in a variety of contexts beyond the indoors like LCD TVs and home/office automation devices, the LCD has expanded its usage to many environments, such as cars and digital signage, and, thus, many temperature variations as well.

As with any substance that requires a specific molecular characteristic or behavior, LCDs have an operating temperature range in which the device, if within, can continue to function properly and well. In addition to that, there is also an ideal storage temperature range to preserve the device until used.

This operating temperature range affects the electronic portion within the device, seen as falling outside the range can cause LCD technology to overheat in hot temperatures or slow down in the cold. As for the liquid crystal layer, it can deteriorate if put in high heat, rendering it and the display itself defective.

In order for the LCD panel to avoid defects, a standard commercial LCD’s operation range and storage range should be kept in mind. Without adaptive features, a typical LCD TV has an operating range from its cold limit of 0°C (32°F) to its heat limit of 50°C (122°F) (other LCD devices’ ranges may vary a bit from these numbers).

The storage range is a bit wider, from -20°C (-4°F) to 60°C (140°F). Though these ranges are quite reasonable for many indoor and even outdoor areas, there are also quite a few regions where temperatures can drop below 0°C or rise above 32°C, and in these conditions, LCDs must be adapted to ensure functionality.

Heat, can greatly affect the electronics and liquid crystals under an LCD screen. In consideration of heat, both external heat and internally generated heat must be taken into consideration.

Seen as the liquid crystals are manipulated in a device by altering their orientations and alignments, heat can disrupt this by randomizing what is meant to be controlled. If this happens, the LCD electronics cannot command a certain formation of the liquid crystal layer under a pixel, and the LED backlighting will not pass through as expected, which can often lead to dark spots, if not an entirely dark image. This inevitably disrupts the display’s readability.

Depending on the upper limit of the operation temperature range, LCD device can be permanently damaged by extreme heat. With long exposure to extreme heat, besides the destruction of the liquid crystals, battery life can shorten, hardware can crack or even melt, response time may slow to prevent even more heat generation from the device.

The LED backlight and the internal circuitry, typically TFT-based in the common TFT LCDs, are components that can generate heat that damages the device and its display. To address this concern with overheating, many devices use cooling fans paired with vents.

Some devices that are used in extremely high ambient temperatures may even require air conditioning. With air vents to carry the heat out, the device can expel it into the surroundings.

In the opposite direction is extreme cold. What typically occurs in the cold is “ghosting” (the burning of an image in the screen through discoloration) and the gradual slowing and lagging of response times. Like heat-affected LCD modules, the extreme temperature can affect the liquid crystals. This layer is a medium between the liquid and solid state, so it is still susceptible to freezing.

An LCD device can be left in freezing temperatures because it will likely not be permanently damaged like in the heat, but it is important to understand the device’s limits and how to take precautions when storing the device. The standard and most common lower-bound storage range limit is -20°C, below freezing, but if possible, it would be best to keep it above that limit, or else there is still a risk of permanent damage.

If the device is not adapted for the cold, it would be good to keep it bundled up, trapping the heat within layers. However, this is only a temporary solution. Adapted, rugged devices have advantages such as screen enclosure insulation for heat level preservation and, in more extreme cases, heaters to generate extra heat to raise the internal temperature to a level above the minimum.

When selecting the appropriate module, it is necessary to understand the device’s expected primary application. The application will decide factors such as display type, environmental conditions, whether or not power consumption is a factor, and the balance between performance and cost. These factors can have an effect on the operation and storage temperature ranges for the device.

Display types have a lot of variation. Choices like alphanumeric or graphic LCD, human-machine interactive LCD modules and touchscreen panels capabilities, the width of the viewing angle, level of contrast ratios, types of backlighting, and liquid crystal alignment methods are often considered. For example, the twisted nematic LCD provides for the fastest response time at the lowest cost, but cannot offer the highest contrast ratio or widest viewing angle.

Environment-based factors must consider things besides the obvious temperature like UV exposure and humidity/moisture, as they all are necessary in finding the perfect fit extreme temperature LCD module.

Besides the LCD modules, recent new products have opened doors in wide temperature range displays, such as OLED displays. OLED displays offer better displays in regard to contrast, brightness, response times, viewing angles, and even power consumption in comparison to traditional LCD displays.

These benefits, in addition to its ability to achieve a wide temperature range, provide more options for consumers in search of high quality displays for extreme climates.

The higher the mux rate, the less time a given group of segments is being addressed , and the worse the display will look. If you refer to our "Basic Operation of an LCD" page, it is easy to see that this is not a good situation.

To understand what happens to the LCD in cold temperatures, we"ll need to go back to the basics of LCD technology. Liquid crystal displays are just like their name suggests... they contain a liquid that is housed between two layers of glass. Liquids begin to freeze as the temperature drops. As the liquid in the display freezes the response time slows down. In other words, it takes longer for the numbers and letters on the display to change (Turn ON or Turn OFF).

The best way I can think to explain the response time of the LCD in cold temperatures is a ceiling fan. When you turn OFF the ceiling fan the blades continue to turn for a few minutes, even though the power if OFF. When you turn ON a ceiling fan the blades will be at full speed in a shorter period of time. At most the blades will be at their max speed within 30 seconds. When talking about an LCD, we talk about when the display is ON (the characters can be seen) or OFF (the characters cannot be seen).

We do not recommend operating our wide temperature (extended temperature) displays below -20°C (-4°F). This is true for all segment displays (static displays or glass displays), 7 (seven) segment, 14 (fourteen) segment, and 16 (sixteen) segment LCD’s.

Alphanumeric LCD displays such as: 8x1 LCD display, 8x2 LCD display, 16x1 LCD display, 16x2 LCD display, 16x4 LCD display, 20x2 LCD display, 20x4 LCD display, 24x2 LCD display, 40x1 LCD display, 40x2 LCD display, and 40x4 LCD display will react the same way.

Professional LCD displays are located in such industries as medical, industrial, theaters, airports, train stations, churches and even schools. They provide the ability to display information to a large body of people or are visible at a great distance. These displays produce large color images and characters that display information such as arrival and departure times and weather conditions. Information can be presented as precisely and attractively as possible.

TFT, OLEDs and Plasma can be customized to meet the needs of a customer, but the tooling cost is very prohibitive. Even if the customer is willing to invest into tooling, the MOQ (Minimum Order Quantity) requirements can reach as high as several thousand. These limitations force customers looking for a professional LCD display to design their product around the LCD. This is no longer true with the introduction of a new technology that offers the ability of low cost tooling and lower MOQ’s but also a wide operating temperature range and ultra-sharp contrast.

UWVDLCD displays are built with a stark black background. Unlike other technologies that use filters to create the black, UWVD LCD displays offer a true black background 100% of the time. There is no ‘dark grey’ or fading of colors that older displays suffered from.

In the past, product design engineers using a professional LCD display were required to design their product around the display module. UWVD now reverses this; the display can be designed and manufactured to meet the needs of the customer’s product.

Professional LCD displays incorporating UWVD technology offer a contrast ratio of greater than 200:1. This contrast can be seen when the display is located a long distance from the audience or end customer.

The operating temperature range of a TFT is at -20C to +70C and plasma displays are rated to at 0C to +40C. OLED displays can operate as low as -40C, but keep in mind that half-life of the blue color is rated at 14K hours (1.6 years on continuous use).

Product design engineers making use of professional LCD displays have many choices when choosing a display technology that would be perfect for their particular product. The UWVD technology may offer a competitive advantage over other competing LCD technology.

The thermoMETER CT is a cost-effective temperature sensor that is integrated with a measuring range of 50 to 600°C and -40 to 900°C. This device possesses a spectral rate ranging from 8 to 14 µm and is characterized by ...

... 8-14 µm.It features a broad measuring range of -50 to 600°C.Built in with one of the smallest IR sensors in the world, it displays extremely short measuring times and is most efficient for fast processes.It also showcases ...

The thermoMETER CT is a non-contact IR-temperature sensor that is ideal for use in a variety of applications including processing of clays, furnaces, plastic, and textile. The unit has the capacity to measure temperatures ...

... easy-to-use pistol grip IR thermometer (sometimes called laser thermometers or non-contact thermometers) for making surface temperature measurements. It has a built-in laser to assist ...

... radiation thermometer. It is a handy type, yet high performance with focusable type, large distance factor and wide temperature range up to a high temperature.

This thermometer is inexpensive easy to used handheld type radiation thermometer with measuring range -40 to 500°C and measuring wavelength 8 to 14μm. This general use thermometer is ...

IR-TE2 is water-proof handheld infrared thermometer with measuring temperature range -40 to 300°C. With its one button operation and laser pointer for measuring location checking, anybody can use the thermometer ...

HEITRONICS transfer radiation thermometers guarantee precise and long-term stable temperature measurements. They are used for calibrating cavity blackbodies and plate radiation sources, radiation thermometers ...

Modern intensity comparison pyrometer (successor of the disappearing filament pyrometer) for precise contol of temperatures ranging between 700 °C and 3500 °C. Target spots as small as 0.1 mm can be achieved. Mikro PV ...

The DTE is a battery powered LCD digital thermometer designed for use in a wide range of industrial and process applications. Similar to our standard DTB instrument, this latest development ...

Infrared thermometer with a built-in contact thermocouple probe. This dual-sensor thermometer is very useful and requires both non-contact and contact temperature measurement. This model has food-grade ...

... gun-type infrared thermometer with laser and backlight for easier targeting and operating. The good temperature range with real-time maximum reading makes the BT63 the ideal tool for various applications.

Robust, easy-to-use and compact, PN 6515 waterproof thermometer is dedicated to temperature control of perishable food and can be used within expertise campaigns in food industry.

... accuracy handheld temperature indicator with two platinum resistance thermometer inputs. The high precision makes the instrument particularly suitable as a portable reference thermometer to use alongside ...

... a mobile phone. It has a dual target laser for aiming at the measuring point. The emission factor can be adjusted. The LCD display is easy to read due to its size and the background lighting.

Microtips’s Automotive Grade LCD Modules are offered in sizes ranging from 3.5 to 12.1 in. with high-brightness backlights. The units are suitable for use in applications such as dials, gauges, clocks and audio/thermostat controls. The LCD modules can be operated in -30 to 85°C and can be either resistive or capacitive. The units use IPS technology for keeping colors accurately vibrant and viewing angles wide.

These LCD Modules, with a standard operating temperature of -30 to 85 degrees Celsius, will allow manufacturers to use these displays in any environment, no matter how harsh the conditions. With an emphasis on robust construction and extended temperature range, these displays are ready to use in automotive applications like dials, gauges, clocks, and audio/thermostat controls. They are available in a variety of sizes ranging from 3.5” to 12.1” with high resolution and can come with high-brightness backlights for sunlight readability. Most utilize the latest IPS technology to keep colors accurately vibrant and viewing angles wide. These displays are available with many different interface technologies such as LVDS and RGB to ensure that our display will work with most controllers. Touch Panels are available on some models which make them perfect for center infotainment consoles. They can be either resistive or capacitive and can be fine tuned to work with gloves if needed. They utilize SPI or I2C to communicate with the host device.

In low temperature environment, liquid crystals will be condensed and cause the screen blanked out. In order to prevent the problem, you may need to add a Glass Heater to your TFT LCD Module.

It can optimize the LCD visual clarity and operate normally by heating up to the right temperature. With Glass Heater, displays and touch screens remain usable in cold, high humidity/low dew point environments and locations where ambient temperature can change quickly.

LCD stands for “liquid crystal display,” but this is a bit of a misnomer. In reality, the technology has no liquid components, so it isn’t susceptible to freezing and expansion in extreme cold. (Remember, many vehicles nowadays have LCD displays on their in-dash radios and CD players, and these have not been known to crack in freezing climates.)

An LED (light-emitting diode) TV is nothing more than an LCD TV that uses LED backlighting. Compared to the LCD’s fluorescent-style backlighting, LEDs are more energy-efficient, but they don’t respond to cold temperatures much differently. One exception is that LED lights may actually shine brighter in cooler temperatures, as long as it is not too cold. But what is too cold?

When it comes to durability in cold temperatures, there is no real difference between LCD and LED TVs. An LCD or LED TV may not perform well under extreme temperature conditions. In the cold, the response time of an HDTV picture may lag. For this reason, many LCD and LED television manuals will specify a safe-operating-temperature range. In most HDTVs, this range is about 50–90°F.

The temperature range for safe storage is typically even wider. Most LCD and LED sets are rated for storage in temps as low as -4°F. Always refer to your television’s manual for actual safe-temperature ranges.

If your cabin gets colder than this in the winter, you may want to consider erring on the side of caution. Cover the set in a soft blanket to protect it from dust and direct sunlight, and then store it in a dry place with above-freezing temperatures for the season, or for however long you plan to be away.

If you decide to leave the TV at the cabin for impromptu winter visits, exercise caution when turning it on in a cold room. Allow time for the cabin to warm up before turning on the TV, otherwise the extreme change in temperature may result in condensation inside the set and subsequent damage to the screen.

So, when you arrive at the cottage and fire up the woodstove, fireplace or heater, wait at least an hour (longer is better) for the screen to reach a temperature within the safe operating range. Sounds like a long time to wait, we know. But just think – you’ll have more time for card games and conversation!

PLYMOUTH, MICH. – Feb. 28, 2018– Kyocera International, Inc. today announced a new line of high-performance, high-resolution liquid-crystal display (LCD) panels specifically designed for automotive Head-Up-Displays (HUDs). These LCDs offer high light transmittance, high resolution, and the industry’s widest operating temperature range for optimal performance in automotive HUD applications.

Developed originally for defense aircraft, HUD technology can improve automotive safety and reduce driver fatigue by projecting vehicle speed, navigation and other data directly onto a car’s windshield – where drivers can view it in their line of sight. This requires a display that performs well in lighting conditions ranging from full sunlight to total darkness. Additionally, since data and images are scaled up when projected onto a windshield, HUD technology requires high-resolution imaging to allow enlargement with no perceptible loss of detail or sharpness. Meeting these requirements in the automotive environment requires imaging components that deliver exceptional luminance, contrast and pixel density, with an extremely wide operating temperature range, since vehicles may travel to the coldest and hottest climates on Earth.

Kyocera’s new HUD LCDs provide light transmittance up to an ultra-high 8.5%, and typical contrast ratios of up to 1700:1. Their low temperature polysilicon technology delivers pixel density of approximately 300ppi – about twice that of conventional LCDs – and an 85-degree viewing angle* with no color shift, through Kyocera’s Advanced Wide Viewing technology (AWVII). Additionally, Kyocera HUD LCDs offer an operating temperature range of -40ºC to +105ºC, the broadest currently available among automotive displays.

“Kyocera brings four decades of LCD innovation to the automotive engineer’s unique challenges when integrating HUD technology into any vehicle platform,” said Kazuaki Ohara, manager of Kyocera’s automotive display sales division. “We are partnering with tier-one automotive brands to help bring this exciting new technology into all vehicles.”

Kyocera is a preferred supplier of high-performance LCD displays for automotive, industrial and medical equipment. All Kyocera TFT-LCDs are RoHS compliant to reduce or eliminate potentially hazardous substances. Please visitwww.kyocera-display.com,call +1-734-416-8500 or emaildisplaysales@kyocera.comfor more information.

Kyocera International, Inc. is a U.S. subsidiary of Kyoto, Japan-based Kyocera Corporation, a diversified technology enterprise that started manufacturing(under the Optrex brand) in 1976. The company’s U.S. LCD assembly, warehousing and distribution are based in Plymouth, Michigan, with LCD sales offices in Michigan, California, Georgia and Washington State.

Kyocera Corporation(NYSE:KYO; TOKYO:6971; www.kyocera.com), the parent and global headquarters of the Kyocera Group, was founded in 1959 as a producer offine ceramics(also known as “advanced ceramics”). By combining these engineered materials with metals and integrating them with other technologies, Kyocera has become a leading supplier of LCDs, industrial ceramics, electronic components, semiconductor packages, cutting tools, solar power generating systems, printers, copiers and mobile phones. During the year ended March 31, 2017, the company’s consolidated net sales totaled 1.42 trillion yen (approx. USD12.7 billion). Kyocera appears on the “Top 100 Global Innovators” list by Clarivate Analytics and is ranked #522 on Forbes magazine’s 2017 “Global 2000” list of the world’s largest publicly traded companies.

The LCD has been widely used in different applications, such as automotive, home appliance, medical, industrial, communication, entertainment, consumer devices, etc. It has been the most popular display technology for more than a decade after surpassing CRT. But the LCD has its genetic drawbacks, such as narrow viewing angle, slow response, and low contrast, limiting its use in some applications. These drawbacks also make LCDs venerable for other new display technologies, OLED (Organic Light Emitting Diode) and Micro LED. Engineers have been working on different ways to improve the LCD drawbacks. Today, we will discuss the LCD contrast affected by temperature and improve LCD contrast with the temperature changes.

From Figure 2, when the voltage increases, the LCD’s transmission is getting lower. When the transmission level reaches 90% of the no voltage applied, we can see the LCD shows images but very light. We call it the threshold voltage (V90 or Vth).

From Figure 3, we can see the LCD voltage decreases with the temperature. From -15oC to +60oC, the curve relatively flat, but when the temperature is lower than -20oC and higher than +70oC, the voltage changes dramatically with temperature, that is why most LCD has an operating temperature of -20oC to +70oC.  Some LCD manufacturers stated that the LCD has an operating temperature range of -30 oC to +80oC, but be ready that the poor contrast has to be accepted with both ends of the temperature.

From Figure 4, we can see the LCD contrast is optimized at a temperature of around +20oC, which is room temperature.  The contrast (CR) decreases with higher and lower temperatures, which can be a big issue for some applications.

Scientists and Engineers of different areas have been trying to improve the LCD contrast under low and high temperatures. But the facts are all of them having trade-off. The users have to balance all the factors to choose the best solutions for their applications. We will explain the most popular ways for LCD to deal with temperature.

It is easier to do. The contrast dramatically changes at a higher temperature because liquid crystal material is close to its clearing point.  The material in the LCD is no longer liquid crystal material anymore; it becomes liquid (like water). Then, the solution will be to increase the clearing point of the material used. Most commercial LCDs use liquid crystal material with a clearing point of around 80oC, making it useable at +70oC. Still, for those conditions, the liquid crystal material used as a clearing point closer to 130oC makes it useable over +100oC theoretically.

Of course, we can imagine that material is costly. Another issue that the high-temperature performance LCDs have a bad performance at low temperature. The response time at low temperatures can be very long.

The heater can be used to heat LCD when the temperature drops below -20oC. Of course, the temperature sensor can be used to switch on/off the heating. Usually, there are 3 kinds of heaters to be used. 1) wire heater, 2) ITO heater on flex, 3) ITO heater on the glass. Depending on the heating speed needed, the heating power can be designed.

Of course, you can see the issue of using a heater in an LCD. The first is the cost; the second is the power of heating. Please prepare to use around 1 to 2w/inch2 power budget in your design.

The biggest liquid crystal material manufacturer in the world, E. Merck claimed that they developed “Flat Fluids,” which makes the curve in  Figure 3 LCD Operating Voltage (Vop) vs Temperature relatively flat from -30oC to +80oC. It is good news for most applications. But the limitation is that Flat Fluids can only be used in TN-type displays also costly.

The good news that many modern LCD controllers include temperature compensation circuitry in the IC design, dramatically makes the design work easier by simply setting the function. But all the LCD temperature compensation circuitry is linear, which can’t match the liquid crystal material voltage curve with temperature. But it is good enough for most applications. See Figure 6.

100% brand new and high quality LCD digital temperature and humidity display meter with external probe. Perfect for use in incubators, brooders, cigar room and other places where you want.

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, digital clocks, calculators, and mobile telephones, including smartphones. LCD screens are also used on consumer electronics products such as DVD players, video game devices and clocks. LCD screens have replaced heavy, bulky cathode-ray tube (CRT) displays in nearly all applications. LCD screens are available in a wider range of screen sizes than CRT and plasma displays, with LCD screens available in sizes ranging from tiny digital watches to very large television receivers. LCDs are slowly being replaced by OLEDs, which can be easily made into different shapes, and have a lower response time, wider color gamut, virtually infinite color contrast and viewing angles, lower weight for a given display size and a slimmer profile (because OLEDs use a single glass or plastic panel whereas LCDs use two glass panels; the thickness of the panels increases with size but the increase is more noticeable on LCDs) and potentially lower power consumption (as the display is only "on" where needed and there is no backlight). OLEDs, however, are more expensive for a given display size due to the very expensive electroluminescent materials or phosphors that they use. Also due to the use of phosphors, OLEDs suffer from screen burn-in and there is currently no way to recycle OLED displays, whereas LCD panels can be recycled, although the technology required to recycle LCDs is not yet widespread. Attempts to maintain the competitiveness of LCDs are quantum dot displays, marketed as SUHD, QLED or Triluminos, which are displays with blue LED backlighting and a Quantum-dot enhancement film (QDEF) that converts part of the blue light into red and green, offering similar performance to an OLED display at a lower price, but the quantum dot layer that gives these displays their characteristics can not yet be recycled.

Since LCD screens do not use phosphors, they rarely suffer image burn-in when a static image is displayed on a screen for a long time, e.g., the table frame for an airline flight schedule on an indoor sign. LCDs are, however, susceptible to image persistence.battery-powered electronic equipment more efficiently than a CRT can be. By 2008, annual sales of televisions with LCD screens exceeded sales of CRT units worldwide, and the CRT became obsolete for most purposes.

Each pixel of an LCD typically consists of a layer of molecules aligned between two transparent electrodes, often made of Indium-Tin oxide (ITO) and two polarizing filters (parallel and perpendicular polarizers), the axes of transmission of which are (in most of the cases) perpendicular to each other. Without the liquid crystal between the polarizing filters, light passing through the first filter would be blocked by the second (crossed) polarizer. Before an electric field is applied, the orientation of the liquid-crystal molecules is determined by the alignment at the surfaces of electrodes. In a twisted nematic (TN) device, the surface alignment directions at the two electrodes are perpendicular to each other, and so the molecules arrange themselves in a helical structure, or twist. This induces the rotation of the polarization of the incident light, and the device appears gray. If the applied voltage is large enough, the liquid crystal molecules in the center of the layer are almost completely untwisted and the polarization of the incident light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the voltage applied across the liquid crystal layer in each pixel, light can be allowed to pass through in varying amounts thus constituting different levels of gray.

The chemical formula of the liquid crystals used in LCDs may vary. Formulas may be patented.Sharp Corporation. The patent that covered that specific mixture expired.

Most color LCD systems use the same technique, with color filters used to generate red, green, and blue subpixels. The LCD color filters are made with a photolithography process on large glass sheets that are later glued with other glass sheets containing a TFT array, spacers and liquid crystal, creating several color LCDs that are then cut from one another and laminated with polarizer sheets. Red, green, blue and black photoresists (resists) are used. All resists contain a finely ground powdered pigment, with particles being just 40 nanometers across. The black resist is the first to be applied; this will create a black grid (known in the industry as a black matrix) that will separate red, green and blue subpixels from one another, increasing contrast ratios and preventing light from leaking from one subpixel onto other surrounding subpixels.Super-twisted nematic LCD, where the variable twist between tighter-spaced plates causes a varying double refraction birefringence, thus changing the hue.

LCD in a Texas Instruments calculator with top polarizer removed from device and placed on top, such that the top and bottom polarizers are perpendicular. As a result, the colors are inverted.

The optical effect of a TN device in the voltage-on state is far less dependent on variations in the device thickness than that in the voltage-off state. Because of this, TN displays with low information content and no backlighting are usually operated between crossed polarizers such that they appear bright with no voltage (the eye is much more sensitive to variations in the dark state than the bright state). As most of 2010-era LCDs are used in television sets, monitors and smartphones, they have high-resolution matrix arrays of pixels to display arbitrary images using backlighting with a dark background. When no image is displayed, different arrangements are used. For this purpose, TN LCDs are operated between parallel polarizers, whereas IPS LCDs feature crossed polarizers. In many applications IPS LCDs have replaced TN LCDs, particularly in smartphones. Both the liquid crystal material and the alignment layer material contain ionic compounds. If an electric field of one particular polarity is applied for a long period of time, this ionic material is attracted to the surfaces and degrades the device performance. This is avoided either by applying an alternating current or by reversing the polarity of the electric field as the device is addressed (the response of the liquid crystal layer is identical, regardless of the polarity of the applied field).

Displays for a small number of individual digits or fixed symbols (as in digital watches and pocket calculators) can be implemented with independent electrodes for each segment.alphanumeric or variable graphics displays are usually implemented with pixels arranged as a matrix consisting of electrically connected rows on one side of the LC layer and columns on the other side, which makes it possible to address each pixel at the intersections. The general method of matrix addressing consists of sequentially addressing one side of the matrix, for example by selecting the rows one-by-one and applying the picture information on the other side at the columns row-by-row. For details on the various matrix addressing schemes see passive-matrix and active-matrix addressed LCDs.

LCDs, along with OLED displays, are manufactured in cleanrooms borrowing techniques from semiconductor manufacturing and using large sheets of glass whose size has increased over time. Several displays are manufactured at the same time, and then cut from the sheet of glass, also known as the mother glass or LCD glass substrate. The increase in size allows more displays or larger displays to be made, just like with increasing wafer sizes in semiconductor manufacturing. The glass sizes are as follows:

Until Gen 8, manufacturers would not agree on a single mother glass size and as a result, different manufacturers would use slightly different glass sizes for the same generation. Some manufacturers have adopted Gen 8.6 mother glass sheets which are only slightly larger than Gen 8.5, allowing for more 50 and 58 inch LCDs to be made per mother glass, specially 58 inch LCDs, in which case 6 can be produced on a Gen 8.6 mother glass vs only 3 on a Gen 8.5 mother glass, significantly reducing waste.AGC Inc., Corning Inc., and Nippon Electric Glass.

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

In 2016, Panasonic developed IPS LCDs with a contrast ratio of 1,000,000:1, rivaling OLEDs. This technology was later put into mass production as dual layer, dual panel or LMCL (Light Modulating Cell Layer) LCDs. The technology uses 2 liquid crystal layers instead of one, and may be used along with a mini-LED backlight and quantum dot sheets.

Since LCDs produce no light of their own, they require external light to produce a visible image.backlight. Active-matrix LCDs are almost always backlit.Transflective LCDs combine the features of a backlit transmissive display and a reflective display.

CCFL: The LCD panel is lit either by two cold cathode fluorescent lamps placed at opposite edges of the display or an array of parallel CCFLs behind larger displays. A diffuser (made of PMMA acrylic plastic, also known as a wave or light guide/guiding plateinverter to convert whatever DC voltage the device uses (usually 5 or 12 V) to ≈1000 V needed to light a CCFL.

EL-WLED: The LCD panel is lit by a row of white LEDs placed at one or more edges of the screen. A light diffuser (light guide plate, LGP) is then used to spread the light evenly across the whole display, similarly to edge-lit CCFL LCD backlights. The diffuser is made out of either PMMA plastic or special glass, PMMA is used in most cases because it is rugged, while special glass is used when the thickness of the LCD is of primary concern, because it doesn"t expand as much when heated or exposed to moisture, which allows LCDs to be just 5mm thick. Quantum dots may be placed on top of the diffuser as a quantum dot enhancement film (QDEF, in which case they need a layer to be protected from heat and humidity) or on the color filter of the LCD, replacing the resists that are normally used.

WLED array: The LCD panel is lit by a full array of white LEDs placed behind a diffuser behind the panel. LCDs that use this implementation will usually have the ability to dim or completely turn off the LEDs in the dark areas of the image being displayed, effectively increasing the contrast ratio of the display. The precision with which this can be done will depend on the number of dimming zones of the display. The more dimming zones, the more precise the dimming, with less obvious blooming artifacts which are visible as dark grey patches surrounded by the unlit areas of the LCD. As of 2012, this design gets most of its use from upscale, larger-screen LCD televisions.

RGB-LED array: Similar to the WLED array, except the panel is lit by a full array of RGB LEDs. While displays lit with white LEDs usually have a poorer color gamut than CCFL lit displays, panels lit with RGB LEDs have very wide color gamuts. This implementation is most popular on professional graphics editing LCDs. As of 2012, LCDs in this category usually cost more than $1000. As of 2016 the cost of this category has drastically reduced and such LCD televisions obtained same price levels as the former 28" (71 cm) CRT based categories.

Monochrome LEDs: such as red, green, yellow or blue LEDs are used in the small passive monochrome LCDs typically used in clocks, watches and small appliances.

Today, most LCD screens are being designed with an LED backlight instead of the traditional CCFL backlight, while that backlight is dynamically controlled with the video information (dynamic backlight control). The combination with the dynamic backlight control, invented by Philips researchers Douglas Stanton, Martinus Stroomer and Adrianus de Vaan, simultaneously increases the dynamic range of the display system (also marketed as HDR, high dynamic range television or FLAD, full-area local area dimming).

The LCD backlight systems are made highly efficient by applying optical films such as prismatic structure (prism sheet) to gain the light into the desired viewer directions and reflective polarizing films that recycle the polarized light that was formerly absorbed by the first polarizer of the LCD (invented by Philips researchers Adrianus de Vaan and Paulus Schaareman),

Due to the LCD layer that generates the desired high resolution images at flashing video speeds using very low power electronics in combination with LED based backlight technologies, LCD technology has become the dominant display technology for products such as televisions, desktop monitors, notebooks, tablets, smartphones and mobile phones. Although competing OLED technology is pushed to the market, such OLED displays do not feature the HDR capabilities like LCDs in combination with 2D LED backlight technologies have, reason why the annual market of such LCD-based products is still growing faster (in volume) than OLED-based products while the efficiency of LCDs (and products like portable computers, mobile phones and televisions) may even be further improved by preventing the light to be absorbed in the colour filters of the LCD.

A pink elastomeric connector mating an LCD panel to circuit board traces, shown next to a centimeter-scale ruler. The conductive and insulating layers in the black stripe are very small.

A standard television receiver screen, a modern LCD panel, has over six million pixels, and they are all individually powered by a wire network embedded in the screen. The fine wires, or pathways, form a grid with vertical wires across the whole screen on one side of the screen and horizontal wires across the whole screen on the other side of the screen. To this grid each pixel has a positive connection on one side and a negative connection on the other side. So the total amount of wires needed for a 1080p display is 3 x 1920 going vertically and 1080 going horizontally for a total of 6840 wires horizontally and vertically. That"s three for red, green and blue and 1920 columns of pixels for each color for a total of 5760 wires going vertically and 1080 rows of wires going horizontally. For a panel that is 28.8 inches (73 centimeters) wide, that means a wire density of 200 wires per inch along the horizontal edge.

The LCD panel is powered by LCD drivers that are carefully matched up with the edge of the LCD panel at the factory level. The drivers may be installed using several methods, the most common of which are COG (Chip-On-Glass) and TAB (Tape-automated bonding) These same principles apply also for smartphone screens that are much smaller than TV screens.anisotropic conductive film or, for lower densities, elastomeric connectors.

Monochrome and later color passive-matrix LCDs were standard in most early laptops (although a few used plasma displaysGame Boyactive-matrix became standard on all laptops. The commercially unsuccessful Macintosh Portable (released in 1989) was one of the first to use an active-matrix display (though still monochrome). Passive-matrix LCDs are still used in the 2010s for applications less demanding than laptop computers and TVs, such as inexpensive calculators. In particular, these are used on portable devices where less information content needs to be displayed, lowest power consumption (no backlight) and low cost are desired or readability in direct sunlight is needed.

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

STN LCDs have to be continuously refreshed by alternating pulsed voltages of one polarity during one frame and pulses of opposite polarity during the next frame. Individual pixels are addressed by the corresponding row and column circuits. This type of display is called response times and poor contrast are typical of passive-matrix addressed LCDs with too many pixels and driven according to the "Alt & Pleshko" drive scheme. Welzen and de Vaan also invented a non RMS drive scheme enabling to drive STN displays with video rates and enabling to show smooth moving video images on an STN display.

Bistable LCDs do not require continuous refreshing. Rewriting is only required for picture information changes. In 1984 HA van Sprang and AJSM de Vaan invented an STN type display that could be operated in a bistable mode, enabling extremely high resolution images up to 4000 lines or more using only low voltages.

High-resolution color displays, such as modern LCD computer monitors and televisions, use an active-matrix structure. A matrix of thin-film transistors (TFTs) is added to the electrodes in contact with the LC layer. Each pixel has its own dedicated transistor, allowing each column line to access one pixel. When a row line is selected, all of the column lines are connected to a row of pixels and voltages corresponding to the picture information are driven onto all of the column lines. The row line is then deactivated and the next row line is selected. All of the row lines are selected in sequence during a refresh operation. Active-matrix addressed displays look brighter and sharper than passive-matrix addressed displays of the same size, and generally have quicker response times, producing much better images. Sharp produces bistable reflective LCDs with a 1-bit SRAM cell per pixel that only requires small amounts of power to maintain an image.

Segment LCDs can also have color by using Field Sequential Color (FSC LCD). This kind of displays have a high speed passive segment LCD panel with an RGB backlight. The backlight quickly changes color, making it appear white to the naked eye. The LCD panel is synchronized with the backlight. For example, to make a segment appear red, the segment is only turned ON when the backlight is red, and to make a segment appear magenta, the segment is turned ON when the backlight is blue, and it continues to be ON while the backlight becomes red, and it turns OFF when the backlight becomes green. To make a segment appear black, the segment is always turned ON. An FSC LCD divides a color image into 3 images (one Red, one Green and one Blue) and it displays them in order. Due to persistence of vision, the 3 monochromatic images appear as one color image. An FSC LCD needs an LCD panel with a refresh rate of 180 Hz, and the response time is reduced to just 5 milliseconds when compared with normal STN LCD panels which have a response time of 16 milliseconds.

Samsung introduced UFB (Ultra Fine & Bright) displays back in 2002, utilized the super-birefringent effect. It has the luminance, color gamut, and most of the contrast of a TFT-LCD, but only consumes as much power as an STN display, according to Samsung. It was being used in a variety of Samsung cellular-telephone models produced until late 2006, when Samsung stopped producing UFB displays. UFB displays were also used in certain models of LG mobile phones.

In-plane switching is an LCD technology that aligns the liquid crystals in a plane parallel to the glass substrates. In this method, the electrical field is applied through opposite electrodes on the same glass substrate, so that the liquid crystals can be reoriented (switched) essentially in the same plane, although fringe fields inhibit a homogeneous reorientation. This requires two transistors for each pixel instead of the single transistor needed for a standard thin-film transistor (TFT) display. The IPS technology is used in everything from televisions, computer monitors, and even wearable devices, especially almost all LCD smartphone panels are IPS/FFS mode. IPS displays belong to the LCD panel family screen types. The other two types are VA and TN. Before LG Enhanced IPS was introduced in 2001 by Hitachi as 17" monitor in Market, the additional transistors resulted in blocking more transmission area, thus requiring a brighter backlight and consuming more power, making this type of display less desirable for notebook computers. Panasonic Himeji G8.5 was using an enhanced version of IPS, also LGD in Korea, then currently the world biggest LCD panel manufacture BOE in China is also IPS/FFS mode TV panel.

In 2011, LG claimed the smartphone LG Optimus Black (IPS LCD (LCD NOVA)) has the brightness up to 700 nits, while the competitor has only IPS LCD with 518 nits and double an active-matrix OLED (AMOLED) display with 305 nits. LG also claimed the NOVA display to be 50 percent more efficient than regular LCDs and to consume only 50 percent of the power of AMOLED displays when producing white on screen.

This pixel-layout is found in S-IPS LCDs. A chevron shape is used to widen the viewing cone (range of viewing directions with good contrast and low color shift).

Vertical-alignment displays are a form of LCDs in which the liquid crystals naturally align vertically to the glass substrates. When no voltage is applied, the liquid crystals remain perpendicular to the substrate, creating a black display between crossed polarizers. When voltage is applied, the liquid crystals shift to a tilted position, allowing light to pass through and create a gray-scale display depending on the amount of tilt generated by the electric field. It has a deeper-black background, a higher contrast ratio, a wider viewing angle, and better image quality at extreme temperatures than traditional twisted-nematic displays.

Blue phase mode LCDs have been shown as engineering samples early in 2008, but they are not in mass-production. The physics of blue phase mode LCDs suggest that very short switching times (≈1 ms) can be achieved, so time sequential color control can possibly be realized and expensive color filters would be obsolete.

Some LCD panels have defective transistors, causing permanently lit or unlit pixels which are commonly referred to as stuck pixels or dead pixels respectively. Unlike integrated circuits (ICs), LCD panels with a few defective transistors are usually still usable. Manufacturers" policies for the acceptable number of defective pixels vary greatly. At one point, Samsung held a zero-tolerance policy for LCD monitors sold in Korea.ISO 13406-2 standard.

Dead pixel policies are often hotly debated between manufacturers and customers. To regulate the acceptability of defects and to protect the end user, ISO released the ISO 13406-2 standard,ISO 9241, specifically ISO-9241-302, 303, 305, 307:2008 pixel defects. However, not every LCD manufacturer conforms to the ISO standard and the ISO standard is quite often interpreted in different ways. LCD panels are more likely to have defects than most ICs due to their larger size. For example, a 300 mm SVGA LCD has 8 defects and a 150 mm wafer has only 3 defects. However, 134 of the 137 dies on the wafer will be acceptable, whereas rejection of the whole LCD panel would be a 0% yield. In recent years, quality control has been improved. An SVGA LCD panel with 4 defective pixels is usually considered defective and customers can request an exchange for a new one.

Some manufacturers, notably in South Korea where some of the largest LCD panel manufacturers, such as LG, are located, now have a zero-defective-pixel guarantee, which is an extra screening process which can then determine "A"- and "B"-grade panels.clouding (or less commonly mura), which describes the uneven patches of changes in luminance. It is most visible in dark or black areas of displayed scenes.

The zenithal bistable device (ZBD), developed by Qinetiq (formerly DERA), can retain an image without power. The crystals may exist in one of two stable orientations ("black" and "white") and power is only required to change the image. ZBD Displays is a spin-off company from QinetiQ who manufactured both grayscale and color ZBD devices. Kent Displays has also developed a "no-power" display that uses polymer stabilized cholesteric liquid crystal (ChLCD). In 2009 Kent demonstrated the use of a ChLCD to cover the entire surface of a mobile phone, allowing it to change colors, and keep that color even when power is removed.

In 2004, researchers at the University of Oxford demonstrated two new types of zero-power bistable LCDs based on Zenithal bistable techniques.e.g., BiNem technology, are based mainly on the surface properties and need specific weak anchoring materials.

Resolution The resolution of an LCD is expressed by the number of columns and rows of pixels (e.g., 1024×768). Each pixel is usually composed 3 sub-pixels, a red, a green, and a blue one. This had been one of the few features of LCD performance that remained uniform among different designs. However, there are newer designs that share sub-pixels among pixels and add Quattron which attempt to efficiently increase the perceived resolution of a display without increasing the actual resolution, to mixed results.

Spatial performance: For a computer monitor or some other display that is being viewed from a very close distance, resolution is often expressed in terms of dot pitch or pixels per inch, which is consistent with the printing industry. Display density varies per application, with televisions generally having a low density for long-distance viewing and portable devices having a high density for close-range detail. The Viewing Angle of an LCD may be important depending on the display and its usage, the limitations of certain display technologies mean the display only displays accurately at certain angles.

Temporal performance: the temporal resolution of an LCD is how well it can display changing images, or the accuracy and the number of times per second the display draws the data it is being given. LCD pixels do not flash on/off between frames, so LCD monitors exhibit no refresh-induced flicker no matter how low the refresh rate.

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

Brightness and contrast ratio: Contrast ratio is the ratio of the brightness of a full-on pixel to a full-off pixel. The LCD itself is only a light valve and does not generate light; the light comes from a backlight that is either fluorescent or a set of LEDs. Brightness is usually stated as the maximum light output of the LCD, which can vary greatly based on the transparency of the LCD and the brightness of the backlight. Brighter backlight allows