difference between tft lcd and oled free sample

TFT displays are also known as an “Active Matrix TFT LCD module” and have an array of thin film transistors fabricated on the glass that makes the LCD. There is one of these transistors for each pixel on the LCD. See our blog post RGB and Color Depth for more on how TFTs show color.

LCDs use voltage applied to a field of microscopic liquid crystals to change the crystal’s orientation. The orientation of the crystals changes the polarization of the liquid crystal creating light or dark pixels on the display.

These pixels are arranged to create characters or graphic images. This type of display may be sunlight-readable and may have a backlight, which allows it to be viewed in dark areas.

Beautiful, complex images: All of our TFT modules are full-color graphic displays. Unlike standard monochrome character displays, you can create complex images for an imaginative user experience.

Thin and light: These are ideal display modules for handheld devices, communications equipment, information displays, and test and measurement equipment.

Single Supply: Most of the TFTs use an integrated controller with built-in voltage generation so only a single 3.3v supply is needed for both the panel power and logic voltage.

Many of our character LCD modules use a standard HD44780 compatible controller, so they can be quickly integrated into a new product or used as a replacement in your existing products.

Many of the LCD controllers on board our graphic LCD display modules also include a CGROM (character generator ROM) which allows for easy character information as well as full bit-mapped graphic information to be shown.

Some of the graphic LCD displays have the ability to render graphics in grayscale, enabling you to show images and elements of your UI (user interface) with more depth and definition.

Because OLEDs are emissive, these displays can always be used in dark environments. There is usually a software command or hardware setting that will allow OLEDs to be dimmed.

Some OLED displays are bright enough to be sunlight readable–these models will typically take more current and may have a shorter rated lifetime. Additionally, OLEDs have extremely wide viewing angles.

What makes OLEDs useful for display construction is that they can be fabricated in bulk. Using OLED fabrication techniques, all the diodes can be made at the same time, at a much lower cost. OLEDs also come in a wide variety of colors.

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In market, LCD means passive matrix LCDs which increase TN (Twisted Nematic), STN (Super Twisted Nematic), or FSTN (Film Compensated STN) LCD Displays. It is a kind of earliest and lowest cost display technology.

LCD screens are still found in the market of low cost watches, calculators, clocks, utility meters etc. because of its advantages of low cost, fast response time (speed), wide temperature range,  low power consumption, sunlight readable with transflective or reflective polarizers etc.  Most of them are monochrome LCD display and belong to passive-matrix LCDs.

TFT LCDs have capacitors and transistors. These are the two elements that play a key part in ensuring that the TFT display monitor functions by using a very small amount of energy without running out of operation.

Normally, we say TFT LCD panels or TFT screens, we mean they are TN (Twisted Nematic) Type TFT displays or TN panels, or TN screen technology. TFT is active-matrix LCDs, it is a kind of LCD technologies.

TFT has wider viewing angles, better contrast ratio than TN displays. TFT display technologies have been widely used for computer monitors, laptops, medical monitors, industrial monitors, ATM, point of sales etc.

Actually, IPS technology is a kind of TFT display with thin film transistors for individual pixels. But IPS displays have superior high contrast, wide viewing angle, color reproduction, image quality etc. IPS screens have been found in high-end applications, like Apple iPhones, iPads, Samsung mobile phones, more expensive LCD monitors etc.

Both TFT LCD displays and IPS LCD displays are active matrix displays, neither of them can produce color, there is a layer of RGB (red, green, blue) color filter in each LCD pixels to make LCD showing colors. If you use a magnifier to see your monitor, you will see RGB color. With switch on/off and different level of brightness RGB, we can get many colors.

Neither of them can’t release color themselves, they have relied on extra light source in order to display. LED backlights are usually be together with them in the display modules as the light sources. Besides, both TFT screens and IPS screens are transmissive, it will need more power or more expensive than passive matrix LCD screens to be seen under sunlight.  IPS screens transmittance is lower than TFT screens, more power is needed for IPS LCD display.

TFT LCD is a mature technology. OLED is a relatively new display technology, being used in more and more applications. As for Micro LED, it is a new generation technology with very promising future. Followings are the pros and cons of each display technology.

TFT Liquid Crystal Display is widely used these days. Since LCD itself doesn"t emit light. TFT LCD relies on white LED backlight to show content. This is an explanation of how TFT LCD works.

Relatively lower contrast：Light needs to pass through LCD glasses, liquid crystal layer, polarizers and color filters. Over 90% is lost. Also, LCD can not display pure black.

Organic Light-Emitting Diode is built from an electro-luminescent layer that contains organic compounds, which emit light in response to an electric current. There are two types of OLED, Passive Matrix OLED (PMOLED) and Active Matrix OLED (AMOLED). These driving methods are similar to LCD"s. PMOLED is controlled sequentially using a matrix addressing scheme, m + n control signals are required to address a m x n display. AMOLED uses a TFT backplane that can switch individual pixels on and off.

Low power consumption and flexible: OLED doesn"t rely on backlight and consumes less power. OLED is essentially created on plastic film. It is bendable and easy to process.

High contrast and vivid color: OLED emits light itself, can produce very bright image with beautiful color. And because OLED can be turned off, it can produce true black.

Stroboscopic effect: most OLED screen uses PWM dimming technology. Some people who are easy perceive stroboscopic frequency may have sore eyes and tears.

​Micro LED, sometimes called μLED is made up of tiny LED, measure less than 100μm. Another way of looking at this is that MicroLEDs are simply traditional LEDs shrunk down and placed into an array.

Replacing organic material with inorganic GaN material eliminates the need of polarizing and encapsulation layer, found in OLED. Micro LED is smaller and thinner, consumes less power.

LCD: liquid crystal display. Works by adjusting the amount of light blocked. Usually has a backlight but might not (clocks, calculators, Nintendo Gameboy). The green-black ones can be very cheap and are a mature technology. Response time can be slow.

TFT: is a type of LCD with a thin film transistor attached to each pixel. All computer LCD screens are TFT since early 2000s; older ones had slower response times and poorer colour. Cost is now very good; power consumption is fairly good but dominated by the backlight. Has to be manufactured out of glass.

LED: light emitting diode. As the name suggests, emits light rather than blocking it like LCD. Used for red/green/blue/white indicator lights everywhere.

Some manufacturers advertise "LED" displays that are TFT screens with a white LED backlight, which is just confusing. Ones that are real LED screens are usually OLED.

OLED: organic LED (rather than silicon or germanium based like regular LEDs). Comparatively recent technology, so cost still quite variable and not available in really large sizes. In theory can be printed on plastic, resulting in lighter flexible displays with good brightness, good power consumption and good response time.

Panox Display provides free connectors for clients who purchase more than five products from us. Our product range includes connectors from Molex, Kyocera, AXE, AXG, JAE, Hiros, and more.

Panox Display provides a customized cover glass/touch panel service. We supply cover glass from Gorilla, AGC, and Panda, which all have excellent optical performance. We also supply driver ICs from Goodix and Focaltech.

If your applications are directly connected to a PC, a cellphone, or Raspberry Pi, and you have enough space to insert a board to input video, Panox Display can provide customized Controller/Driver boards with input connections for VGA, HDMI, DVI, DP, Type-C video input, MIPI, RGB, LVDS, and eDP.

The functions of our boards include, but are not limited to, adjustment of brightness, sound output, touch interface, extra data transmission, and gyroscope.

The VR Display we provide includes 2.1 inch, 2.54 inch, 2.9 inch, 2.95 inch, 3 inch, 3.5 inch, 3.81 inch, 5.55 inch, 6 inch. For micro OLED can be used on VR, we provide 0.71 inch 1920x1080 display.

A lot of people might be thinking, what"s the impact of the screen? It"s actually quite important. You"ll understand after you read this article. Today, let"s dig deeper into some of the "secrets" of VR displays.

Now LCD is the most common VR device screen on the market, and a few VR products use OLED screens and Mirco-OLED screens. Micro OLED is unfamiliar for VR players. Arpara 5K PC VR, the world"s first VR device, is using the micro-OLED display.

At present, the VR hamlet mostly uses "TFT-LCD" (thin film transistor liquid crystal display) technology, which consists of two glass substrates sandwiched with a layer of liquid crystal, the upper glass substrate is a color filter, and the lower glass layer is embedded with the transistor, When the electric field generated by the current passing through the transistor changes, the original rotating arrangement of the liquid crystal molecules will be reversed, which will change the rotation amplitude of the light through, and shine on the color filter in different proportions, and then generate different colors.

LCD technology has been quite mature, used in general computer and TV screens, also used in VR screens, and the cost is low, has become the basic technology of consumer products.

At present, the most fatal problem of LCD is that the liquid crystal layer can not be completely closed, so if the LCD shows black, some light will pass through the color layer, so the black of LCD is actually a gray mixture of white and black, compared to pure black.

OLED(Organic Light-emitting Diode), is based on an Organic light-emitting layer made of indium tin oxide (ITO) glass and covered with a low-work function metal electrode on the light-emitting layer. According to the driving mode, OLED includes AMOLED and PMOLED.

Driven by the external voltage, the positive and cathode electrons will combine in the luminescent layer, generate energy and emit light, and generate Red, Green, and Blue primary colors due to different material characteristics to form the basic colors.

We know that the color of the screen is displayed by pixels, and it takes time for pixels to change from color 1 to color 2. This time is called grayscale response time.

If the gray-scale response time is too long, the pixel in images fast sliding too late that resulting from the color 1 to 2 in the picture, will appear on the vision ghosting, ghosting extremely influence visual perception, the OLED screen is almost without any delay, and the LCD screen, even if it is apple"s top LCD, have a longer response time.

OLED is not the same as LCD screens with black color. Because OLED displays black, the pixels in the black area can be turned off directly to achieve an almost pure black effect. In contrast, OLEDs have excellent contrast and lower power consumption.

To sum up OLED color characters in one sentence: OLED is an oil painting, with pure and delicate colors, while LCD is a watercolor painting, with hazy and light colors. I think people can tell the difference between a high-end OLED and an LCD at a glance.

Although OLED presents a bright picture, has low power consumption, and can be bent, the organic materials will be oxidized, so the life is relatively short, and the color-burning problem does occur. Coupled with the high cost and high technology content, it is mostly suitable for small screens, such as mobile phone screens. In recent years, a handful of VR helmets have used OLED screens.

Mrico-Oled is a new high-level microdisplay technology. Micro OLEDs (silicon-based) consist of organic light-emitting materials sandwiched between two electrodes, diodes that emit light when an electric current flows through them. The desired color is then generated through the filter. The micro OLED light source module is generated by depositing the OLED onto the substrate using vapor deposition.

For example, to produce silicon-based OLED modules, OLED is deposited onto a silicon substrate or semiconductor wafer. In addition to being self-luminous like OLED, micro-OLED help makes thinner, smaller, and more energy-efficient panels. Their shorter response times and higher luminous efficiency also enable the production of high PPI(pixels per inch) displays.

Micro OLED microdisplay devices have the advantages of OLED self-lighting, thin, light, large viewing Angle, short response time, and high luminescence efficiency. Moreover, it is easier to achieve the application effect of high PPI (pixel density), small size, easy to carry, and low power consumption, which is especially suitable for near-eye display devices.

Although VR products on the market have been developed for many years, due to immature technology, they are prone to dizziness, have low resolution, are large in size, expensive. To avoid vertigo, the screen resolution had to be raised from 500 PPI to 2,000 PPI. Micro-OLEDs meet the needs of VR headsets and lenses. Therefore, after years of polishing, Arpara chose to launch the world"s first VR device based on micro-OLED display technology - Arpara 5K PC VR.

As we said earlier, micro-OLED uses pixel self-lighting technology to easily achieve a wide range of colors. For example, our Arpara 5K VR with Mirco-OLED screen covers 90% of the DCI-P3 range, which is the standard for evaluating display capabilities in the film industry. It can reflect the color expression of the product when watching film and television content.

The following figure shows the corresponding color space of the Arpara 5K VR screen, which is highly identical to the DCI-P3 standard color space. The area ratio reaches 94% DCI-P3, and the coverage reaches 90%.

Pixels are small, individually lit elements that are emitted in an array to create a display. For various reasons, pixels sometimes have difficulty packing tightly together, and this causes the gaps between them to not light up. The "fill factor" of the display describes the ratio of the actual lit area to the unlit area. On a display with a low fill coefficient, the user is easy to perceive the dark space between pixels, which leads to the screen effect.

To reduce the screen effect, the filling coefficient should be increased, and at the same time, the pixel density should be increased to minimize the absolute value of the gap between pixels.

Let"s go back and mention the comparison of the previous three screens. For LCD screen, there is a high density of LCD display, but because the LCD display device is a transparent type, its pixel driving circuit can only be placed in a pixel gap, this leads to a certain gap between pixels to place the drive circuit, so even if the high-resolution LCD screen, also cannot avoid the Screen Door Effect. The picture below is an example of a square RGB arrangement of LCD pixels, in which the black part is the driving circuit part (the picture is a schematic, in fact, we need to make a better look, please forgive me)

Relatively speaking, because the OLED material is a self-emitting device, the driver circuit can be placed on the underlying substrate, so there is no dark spot of the driver circuit between pixels.

For large-size OLED screens such as AMOLED, the current fill coefficient is still low, so there are blank areas between the screen pixels, as shown below:

The Micro OLED technology selected by Arpara can well control the pixel gap and greatly increase the pixel filling ratio. The schematic diagram is as follows:

Then again, micro-OLED has a big advantage in the small display market. As the applications of VR and AR displays gradually shift from gaming and military fields to healthcare, education, retail, and other fields, the market continues to expand, and more and more consumers demands resolution and avoidance of display lag. In this case, researchers will start to develop a new generation of display technology with high resolution, high brightness, high contrast, and fast response. At present, micro-OLED is most widely used in military, industrial and medical fields. VR is likely to be the next big thing.

Focus Displays offers a wide range of standard full color TFT displays. 64 million unique colors, high brightness, sharp contrast, -30C operating temperature, and fast response time are all good descriptions of a TFT display. This is why TFT technology is one of the most popular choices for a new product.

Thin Film Transistor (TFT) display technology can be seen in products such as laptop computers, cell phones, tablets, digital cameras, and many other products that require color. TFT’s are active matrix displays which offers exceptional viewing experiences especially when compared to other passive matrix technologies. The clarity on TFT displays is outstanding; and they possess a longer half-life than some types of OLEDs and range in sizes from less than an inch to over 15 inches.

Cold-Cathode Fluorescent Lamp (CCFL) is an AC driven backlight that requires an inverter to convert DC to AC. The AC signal and inverter may generate EMI (Electromagnetic interference) and arcing; Arcing must be eliminated for Intrinsically Safe products.

CCFL’s are still available, but are becoming a legacy (obsolete) component. TFT displays equipped with a CCFL require higher MOQs (Minimum Order Quantities) than displays with LED backlights.

Red, Green and Blue (RGB) backlights are built with either a single LED that produces red, green and blue colors or with three separate Red, Green or Blue LEDs.

RGB backlights require a controller to regulate the different intensities of each color. The controller’s function is to combine unique levels of Red, Green and Blue to produce any of 64M different colors.

Backlight brightness (Luminance) is measured in nits. A nit being the amount of light that one candle delivers in a 1 square meter box. The intensity of the LED backlight can be critical when operating in low light or in direct sun light and is usually controlled by adjusting the DC voltage. In many applications this is accomplished through pulse-width modulation (PWM)

The majority of TFT displays contain a touch panel, or touch screen. The touch panel is a touch-sensitive transparent overlay mounted on the front of the display glass. Allowing for interaction between the user and the LCD display.

Some touch panels require an independent driver IC; which can be included in the TFT display module or placed on the customer’s Printed Circuit Board (PCB). Touch screens make use of coordinate systems to locate where the user touched the screen.

Resistive touch panels are the lowest cost option and are standard equipment on many TFT modules. They are more common on smaller TFT displays, but can still be incorporated on larger modules.

Resistive touch panels are constructed using flexible materials with an air gap between and are coated with a resistive layer. When an object applies pressure to the top layer, it makes contact with microdots located on the bottom layer. This allows the touch screen to find the location of the touch using X and Y coordinates.

Custom resistive touch screens are an option if the customer requires a seal or gasket to be in contact with the glass and not in contact with the touch panel.

They also have the added advantage of operating in a wide temperature range and environments, including anything from the arctic cold of Alaska to the extreme heat of Death Valley.

Capacitive touch panels have become popular with such software as Windows 8®, Android® and Apple®. Additionally it is used in products such as cell phones and tablets, where multi-touch and zoom capabilities are important.

Contrast ratio, or static contrast ratio, is one way to measure the sharpness of the TFT LCD display. This ratio is the difference between the darkest black and the brightest white the display is able to produce. The higher the number on the left, the sharper the image. A typical contrast ratio for TFT may be 300:1. This number ratio means that the white is 300 times brighter than the black.

TFT LCD displays are measured in inches; this is the measurement of the diagonal distance across the glass. Common TFT sizes include: 1.77”, 2.4”, 2.8”, 3”, 4.3”, 5”, 5.7”, 5.8”, 7”, 10.2”, 12.1 and 15”.

As a general rule, the larger the size of the glass the higher the cost of the display, but there are exceptions to this rule. A larger display may be less expensive than a smaller display if the manufacture produces higher quantities of the larger displays. When selecting your color display, be sure to ask what the cost is for one size smaller and one size larger. It may be worth modifying your design requirements.

TFT resolution is the number of dots or pixels the display contains. It is measured by the number of dots along the horizontal (X axis) and the dots along the vertical (Y axis).

Certain combinations of width and height are standardized and typically given a name and a letter representation that is descriptive of its dimensions. Popular names given to the TFT LCD displays resolution include:

Transmissive displays must have the backlight on at all times to read the display, but are not the best option in direct sunlight unless the backlight is 750 Nits or higher. A majority of TFT displays are Transmissive, but they will require more power to operate with a brighter backlight.

Drivers update and refresh the pixels (Picture Elements) of a display. Each driver is assigned a set number of pixels. If there are more pixels than a single driver can handle, then an additional drivers are added.

A primary job of the driver is to refresh each pixel. In passive TFT displays, the pixel is refreshed and then allowed to slowly fade (aka decay) until refreshed again. The higher the refresh frequency, the sharper the displays contrast.

The controller does just what its name suggest. It controls the drivers. There is only one controller per display no matter how many drivers. A complex graphic display with several thousand pixels will contain one controller and several drivers.

The TFT display (minus touch screen/backlight) alone will contain one controller/driver combination. These are built into the display so the design engineer does not need to locate the correct hardware.

Response Time is the measurement of time it takes for a pixel/segment to change from black (OFF state) to white (ON state) and then back to black again. In other words, how fast the picture can be changed. A slow response time can result in the blurring of the picture in games, movies and even cad type programs.

If you do not see a Thin Film Transistor (TFT) Display module that meets your specifications, or you need a replacement TFT, we can build a custom TFT displays to meet your requirements. Custom TFTs require a one-time tooling fee and may require higher MOQs.

Ready to order samples for your TFT design? Contact one of our US-based technical support people today concerning your design requirements. Note: We can provide smaller quantities for samples and prototyping.

Focus LCDs can provide many accessories to go with your display. If you would like to source a connector, cable, test jig or other accessory preassembled to your LCD (or just included in the package), our team will make sure you get the items you need.Get in touch with a team member today to accessorize your display!

Focus Display Solutions (aka: Focus LCDs) offers the original purchaser who has purchased a product from the FocusLCDs.com a limited warranty that the product (including accessories in the product"s package) will be free from defects in material or workmanship.

Founded in 2016(head office in 2009). The factory is located in Dongguan City, Guangdong Province of China which covers area of 1200 square meters and has more than 80 front-line employees and 4 automatic production lines.

Our Main products including a Small LCD screen 0.96inch to 13.3inch, TFT LCD display modules, AMOLED displays, OLED with capacitive touchscreen display. We also expanding our product range to flexible OLED screens as well as Transparent LCD displays. We have to say, you can find a variety of different displays in our company.  Most of our products are widely used in smartwatch wearable device, automotive industry, Smart Home device, industrial control machine, Portable POS System, Gaming console, Smart home robot, Handheld devices, Household appliances like Sweeping robot, other communication devices like IP phone, Smart Security equipment, And other fields. All developed products have passed CE, ROHS, and other certifications.

An organic light-emitting diode (OLED or organic LED), also known as organic electroluminescent (organic EL) diode,light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current. This organic layer is situated between two electrodes; typically, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, and portable systems such as smartphones and handheld game consoles. A major area of research is the development of white OLED devices for use in solid-state lighting applications.

There are two main families of OLED: those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates a light-emitting electrochemical cell (LEC) which has a slightly different mode of operation. An OLED display can be driven with a passive-matrix (PMOLED) or active-matrix (AMOLED) control scheme. In the PMOLED scheme, each row and line in the display is controlled sequentially, one by one,thin-film transistor (TFT) backplane to directly access and switch each individual pixel on or off, allowing for higher resolution and larger display sizes.

OLED is fundamentally different from LED which is based on a p-n diode structure. In LEDs doping is used to create p- and n- regions by changing the conductivity of the host semiconductor. OLEDs do not employ a p-n structure. Doping of OLEDs is used to increase radiative efficiency by direct modification of the quantum-mechanical optical recombination rate. Doping is additionally used to determine the wavelength of photon emission.

An OLED display works without a backlight because it emits its own visible light. Thus, it can display deep black levels and can be thinner and lighter than a liquid crystal display (LCD). In low ambient light conditions (such as a dark room), an OLED screen can achieve a higher contrast ratio than an LCD, regardless of whether the LCD uses cold cathode fluorescent lamps or an LED backlight. OLED displays are made in the same way as LCDs, but after TFT (for active matrix displays), addressable grid (for passive matrix displays) or indium-tin oxide (ITO) segment (for segment displays) formation, the display is coated with hole injection, transport and blocking layers, as well with electroluminescent material after the first 2 layers, after which ITO or metal may be applied again as a cathode and later the entire stack of materials is encapsulated. The TFT layer, addressable grid or ITO segments serve as or are connected to the anode, which may be made of ITO or metal.transparent displays being used in smartphones with optical fingerprint scanners and flexible displays being used in foldable smartphones.

André Bernanose and co-workers at the Nancy-Université in France made the first observations of electroluminescence in organic materials in the early 1950s. They applied high alternating voltages in air to materials such as acridine orange dye, either deposited on or dissolved in cellulose or cellophane thin films. The proposed mechanism was either direct excitation of the dye molecules or excitation of electrons.

In 1960, Martin Pope and some of his co-workers at New York University developed ohmic dark-injecting electrode contacts to organic crystals.work functions) for hole and electron injecting electrode contacts. These contacts are the basis of charge injection in all modern OLED devices. Pope"s group also first observed direct current (DC) electroluminescence under vacuum on a single pure crystal of anthracene and on anthracene crystals doped with tetracene in 1963volts. The proposed mechanism was field-accelerated electron excitation of molecular fluorescence.

Pope"s group reported in 1965exciton energy level. Also in 1965, Wolfgang Helfrich and W. G. Schneider of the National Research Council in Canada produced double injection recombination electroluminescence for the first time in an anthracene single crystal using hole and electron injecting electrodes,Dow Chemical researchers patented a method of preparing electroluminescent cells using high-voltage (500–1500 V) AC-driven (100–3000Hz) electrically insulated one millimetre thin layers of a melted phosphor consisting of ground anthracene powder, tetracene, and graphite powder.

The first Polymer LED (PLED) to be created was by Roger Partridge at the National Physical Laboratory in the United Kingdom. It used a film of poly(N-vinylcarbazole) up to 2.2 micrometers thick located between two charge-injecting electrodes. The light generated was readily visible in normal lighting conditions though the polymer used had 2 limitations; low conductivity and the difficulty of injecting electrons.

Research into polymer electroluminescence culminated in 1990, with J. H. Burroughes et al. at the Cavendish Laboratory at Cambridge University, UK, reporting a high-efficiency green light-emitting polymer-based device using 100nm thick films of poly(p-phenylene vinylene).plastic electronics and OLED research and device production grew rapidly.et al. at Yamagata University, Japan in 1995, achieved the commercialization of OLED-backlit displays and lighting.

In 1999, Kodak and Sanyo had entered into a partnership to jointly research, develop, and produce OLED displays. They announced the world"s first 2.4-inch active-matrix, full-color OLED display in September the same year.

Manufacturing of small molecule OLEDs was started in 1997 by Pioneer Corporation, followed by TDK in 2001 and Samsung-NEC Mobile Display (SNMD), which later became one of the world"s largest OLED display manufacturers - Samsung Display, in 2002.

The Sony XEL-1, released in 2007, was the first OLED television.Universal Display Corporation, one of the OLED materials companies, holds a number of patents concerning the commercialization of OLEDs that are used by major OLED manufacturers around the world.

On 5 December 2017, JOLED, the successor of Sony and Panasonic"s printable OLED business units, began the world"s first commercial shipment of inkjet-printed OLED panels.

A typical OLED is composed of a layer of organic materials situated between two electrodes, the anode and cathode, all deposited on a substrate. The organic molecules are electrically conductive as a result of delocalization of pi electrons caused by conjugation over part or all of the molecule. These materials have conductivity levels ranging from insulators to conductors, and are therefore considered organic semiconductors. The highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of organic semiconductors are analogous to the valence and conduction bands of inorganic semiconductors.

Originally, the most basic polymer OLEDs consisted of a single organic layer. One example was the first light-emitting device synthesised by J. H. Burroughes et al., which involved a single layer of poly(p-phenylene vinylene). However multilayer OLEDs can be fabricated with two or more layers in order to improve device efficiency. As well as conductive properties, different materials may be chosen to aid charge injection at electrodes by providing a more gradual electronic profile,quantum efficiency (up to 19%) by using a graded heterojunction.

During operation, a voltage is applied across the OLED such that the anode is positive with respect to the cathode. Anodes are picked based upon the quality of their optical transparency, electrical conductivity, and chemical stability.electrons flows through the device from cathode to anode, as electrons are injected into the LUMO of the organic layer at the cathode and withdrawn from the HOMO at the anode. This latter process may also be described as the injection of electron holes into the HOMO. Electrostatic forces bring the electrons and the holes towards each other and they recombine forming an exciton, a bound state of the electron and hole. This happens closer to the electron-transport layer part of the emissive layer, because in organic semiconductors holes are generally more mobile than electrons. The decay of this excited state results in a relaxation of the energy levels of the electron, accompanied by emission of radiation whose frequency is in the visible region. The frequency of this radiation depends on the band gap of the material, in this case the difference in energy between the HOMO and LUMO.

As electrons and holes are fermions with half integer spin, an exciton may either be in a singlet state or a triplet state depending on how the spins of the electron and hole have been combined. Statistically three triplet excitons will be formed for each singlet exciton. Decay from triplet states (phosphorescence) is spin forbidden, increasing the timescale of the transition and limiting the internal efficiency of fluorescent devices. Phosphorescent organic light-emitting diodes make use of spin–orbit interactions to facilitate intersystem crossing between singlet and triplet states, thus obtaining emission from both singlet and triplet states and improving the internal efficiency.

Indium tin oxide (ITO) is commonly used as the anode material. It is transparent to visible light and has a high work function which promotes injection of holes into the HOMO level of the organic layer. A second conductive (injection) layer is typically added, which may consist of PEDOT:PSS,barium and calcium are often used for the cathode as they have low work functions which promote injection of electrons into the LUMO of the organic layer.aluminium to avoid degradation. Two secondary benefits of the aluminum capping layer include robustness to electrical contacts and the back reflection of emitted light out to the transparent ITO layer.

Experimental research has proven that the properties of the anode, specifically the anode/hole transport layer (HTL) interface topography plays a major role in the efficiency, performance, and lifetime of organic light-emitting diodes. Imperfections in the surface of the anode decrease anode-organic film interface adhesion, increase electrical resistance, and allow for more frequent formation of non-emissive dark spots in the OLED material adversely affecting lifetime. Mechanisms to decrease anode roughness for ITO/glass substrates include the use of thin films and self-assembled monolayers. Also, alternative substrates and anode materials are being considered to increase OLED performance and lifetime. Possible examples include single crystal sapphire substrates treated with gold (Au) film anodes yielding lower work functions, operating voltages, electrical resistance values, and increasing lifetime of OLEDs.

Single carrier devices are typically used to study the kinetics and charge transport mechanisms of an organic material and can be useful when trying to study energy transfer processes. As current through the device is composed of only one type of charge carrier, either electrons or holes, recombination does not occur and no light is emitted. For example, electron only devices can be obtained by replacing ITO with a lower work function metal which increases the energy barrier of hole injection. Similarly, hole only devices can be made by using a cathode made solely of aluminium, resulting in an energy barrier too large for efficient electron injection.

Balanced charge injection and transfer are required to get high internal efficiency, pure emission of luminance layer without contaminated emission from charge transporting layers, and high stability. A common way to balance charge is optimizing the thickness of the charge transporting layers but is hard to control. Another way is using the exciplex. Exciplex formed between hole-transporting (p-type) and electron-transporting (n-type) side chains to localize electron-hole pairs. Energy is then transferred to luminophore and provide high efficiency. An example of using exciplex is grafting Oxadiazole and carbazole side units in red diketopyrrolopyrrole-doped Copolymer main chain shows improved external quantum efficiency and color purity in no optimized OLED.

Organic small-molecule electroluminescent materials have the advantages of a wide variety, easy to purify, and strong chemical modifications. In order to make the luminescent materials to emit light as required, some chromophores or unsaturated groups such as alkene bonds and benzene rings will usually be introduced in the molecular structure design to change the size of the conjugation range of the material, so that the photophysical properties of the material changes. In general, the larger the range of π-electron conjugation system, the longer the wavelength of light emitted by the material. For instance, with the increase of the number of benzene rings, the fluorescence emission peak of benzene, naphthalene, anthracene,anthracenes, biphenyl acetylene aryl derivatives, coumarin derivatives,Ching W. Tang et al.Eastman Kodak. The term OLED traditionally refers specifically to this type of device, though the term SM-OLED is also in use.

Molecules commonly used in OLEDs include organometallic chelates (for example Alq3, used in the organic light-emitting device reported by Tang et al.), fluorescent and phosphorescent dyes and conjugated dendrimers. A number of materials are used for their charge transport properties, for example triphenylamine and derivatives are commonly used as materials for hole transport layers.perylene, rubrene and quinacridone derivatives are often used.3 has been used as a green emitter, electron transport material and as a host for yellow and red emitting dyes.

Because of the structural flexibility of small-molecule electroluminescent materials, thin films can be prepared by vacuum vapor deposition, which is more expensive and of limited use for large-area devices. The vacuum coating system, however, can make the entire process from film growth to OLED device preparation in a controlled and complete operating environment, helping to obtain uniform and stable films, thus ensuring the final fabrication of high-performance OLED devices.However, small molecule organic dyes are prone to fluorescence quenching

Polymer light-emitting diodes (PLED, P-OLED), also light-emitting polymers (LEP), involve an electroluminescent conductive polymer that emits light when connected to an external voltage. They are used as a thin film for full-spectrum colour displays. Polymer OLEDs are quite efficient and require a relatively small amount of power for the amount of light produced.

Vacuum deposition is not a suitable method for forming thin films of polymers. If the polymeric OLED films are made by vacuum vapor deposition, the chain elements will be cut off and the original photophysical properties will be compromised. However, polymers can be processed in solution, and spin coating is a common method of depositing thin polymer films. This method is more suited to forming large-area films than thermal evaporation. No vacuum is required, and the emissive materials can also be applied on the substrate by a technique derived from commercial inkjet printing.Langmuir-Blodgett film.

Typical polymers used in PLED displays include derivatives of poly(p-phenylene vinylene) and polyfluorene. Substitution of side chains onto the polymer backbone may determine the colour of emitted lightring opening metathesis polymerization.

Phosphorescent organic light-emitting diodes use the principle of electrophosphorescence to convert electrical energy in an OLED into light in a highly efficient manner,

The heavy metal atom at the centre of these complexes exhibits strong spin-orbit coupling, facilitating intersystem crossing between singlet and triplet states. By using these phosphorescent materials, both singlet and triplet excitons will be able to decay radiatively, hence improving the internal quantum efficiency of the device compared to a standard OLED where only the singlet states will contribute to emission of light.

Applications of OLEDs in solid state lighting require the achievement of high brightness with good CIE coordinates (for white emission). The use of macromolecular species like polyhedral oligomeric silsesquioxanes (POSS) in conjunction with the use of phosphorescent species such as Ir for printed OLEDs have exhibited brightnesses as high as 10,000cd/m2.

a) Bottom-emitting and b) top-emitting OLED structures; c,d) Schematic diagrams based on bottom-emitting and top-emitting OLEDs with low and high contrast ratio, respectively.

The bottom-emission organic light-emitting diode (BE-OLED) is the architecture that was used in the early-stage AMOLED displays. It had a transparent anode fabricated on a glass substrate, and a shiny reflective cathode. Light is emitted from the transparent anode direction. To reflect all the light towards the anode direction, a relatively thick metal cathode such as aluminum is used. For the anode, high-transparency indium tin oxide (ITO) was a typical choice to emit as much light as possible.thin film transistor (TFT) substrate, and the area from which light can be extracted is limited and the light emission efficiency is reduced.

An alternative configuration is to switch the mode of emission. A reflective anode, and a transparent (or more often semi-transparent) cathode are used so that the light emits from the cathode side, and this configuration is called top-emission OLED (TE-OLED). Unlike BEOLEDs where the anode is made of transparent conductive ITO, this time the cathode needs to be transparent, and the ITO material is not an ideal choice for the cathode because of a damage issue due to the sputtering process.transmittance and high conductivity.

Since both electrodes are reflective in TEOLED, light reflections can happen within the diode, and they cause more complex interferences than those in BEOLEDs. In addition to the two-beam interference, there exists a multi-resonance interference between two electrodes. Because the structure of TEOLEDs is similar to that of the Fabry-Perot resonator or laser resonator, which contains two parallel mirrors comparable to the two reflective electrodes),

In the case of OLED, that means the cavity in a TEOLED could be especially designed to enhance the light output intensity and color purity with a narrow band of wavelengths, without consuming more power. In TEOLEDs, the microcavity effect commonly occurs, and when and how to restrain or make use of this effect is indispensable for device design. To match the conditions of constructive interference, different layer thicknesses are applied according to the resonance wavelength of that specific color. The thickness conditions are carefully designed and engineered according to the peak resonance emitting wavelengths of the blue (460 nm), green (530 nm), and red (610 nm) color LEDs. This technology greatly improves the light-emission efficiency of OLEDs, and are able to achieve a wider color gamut due to high color purity.

In "white + color filter method," red, green, and blue emissions are obtained from the same white-light LEDs using different color filters.uneven degradation rate of blue pixels vs. red and green pixels. Disadvantages of this method are low color purity and contrast. Also, the filters absorb most of the light waves emitted, requiring the background white light to be relatively strong to compensate for the drop in brightness, and thus the power consumption for such displays can be higher.

Color filters can also be implemented into bottom- and top-emission OLEDs. By adding the corresponding RGB color filters after the semi-transparent cathode, even purer wavelengths of light can be obtained. The use of a microcavity in top-emission OLEDs with color filters also contributes to an increase in the contrast ratio by reducing the reflection of incident ambient light.

Transparent OLEDs use transparent or semi-transparent contacts on both sides of the device to create displays that can be made to be both top and bottom emitting (transparent). TOLEDs can greatly improve contrast, making it much easier to view displays in bright sunlight.Head-up displays, smart windows or augmented reality applications.

Stacked OLEDs use a pixel architecture that stacks the red, green, and blue subpixels on top of one another instead of next to one another, leading to substantial increase in gamut and color depth,

In contrast to a conventional OLED, in which the anode is placed on the substrate, an Inverted OLED uses a bottom cathode that can be connected to the drain end of an n-channel TFT especially for the low cost amorphous silicon TFT backplane useful in the manufacturing of AMOLED displays.

The most commonly used patterning method for organic light-emitting displays is shadow masking during film deposition,photochemical machining, reminiscent of old CRT shadow masks, are used in this process. The dot density of the mask will determine the pixel density of the finished display.−5Pa. An oxygen meter ensures that no oxygen enters the chamber as it could damage (through oxidation) the electroluminescent material, which is in powder form. The mask is aligned with the mother substrate before every use, and it is placed just below the substrate. The substrate and mask assembly are placed at the top of the deposition chamber.virtual reality headsets.

Although the shadow-mask patterning method is a mature technology used from the first OLED manufacturing, it causes many issues like dark spot formation due to mask-substrate contact or misalignment of the pattern due to the deformation of shadow mask. Such defect formation can be regarded as trivial when the display size is small, however it causes serious issues when a large display is manufactured, which brings significant production yield loss. To circumvent such issues, white emission devices with 4-sub-pixel color filters (white, red, green and blue) have been used for large televisions. In spite of the light absorption by the color filter, state-of-the-art OLED televisions can reproduce color very well, such as 100% NTSC, and consume little power at the same time. This is done by using an emission spectrum with high human-eye sensitivity, special color filters with a low spectrum overlap, and performance tuning with color statistics into consideration.

Like ink jet material deposition, inkjet etching (IJE) deposits precise amounts of solvent onto a substrate designed to selectively dissolve the substrate material and induce a structure or pattern. Inkjet etching of polymer layers in OLED"s can be used to increase the overall out-coupling efficiency. In OLEDs, light produced from the emissive layers of the OLED is partially transmitted out of the device and partially trapped inside the device by total internal reflection (TIR). This trapped light is wave-guided along the interior of the device until it reaches an edge where it is dissipated by either absorption or emission. Inkjet etching can be used to selectively alter the polymeric layers of OLED structures to decrease overall TIR and increase out-coupling efficiency of the OLED. Compared to a non-etched polymer layer, the structured polymer layer in the OLED structure from the IJE process helps to decrease the TIR of the OLED device. IJE solvents are commonly organic instead of water-based due to their non-acidic nature and ability to effectively dissolve materials at temperatures under the boiling point of water.

Transfer-printing is an emerging technology to assemble large numbers of parallel OLED and AMOLED devices efficiently. It takes advantage of standard metal deposition, photolithography, and etching to create alignment marks commonly on glass or other device substrates. Thin polymer adhesive layers are applied to enhance resistance to particles and surface defects. Microscale ICs are transfer-printed onto the adhesive surface and then baked to fully cure adhesive layers. An additional photosensitive polymer layer is applied to the substrate to account for the topography caused by the printed ICs, reintroducing a flat surface. Photolithography and etching removes some polymer layers to uncover conductive pads on the ICs. Afterwards, the anode layer is applied to the device backplane to form the bottom electrode. OLED layers are applied to the anode layer with conventional vapor deposition, and covered with a conductive metal electrode layer. As of 2011mm × 400mm. This size limit needs to expand for transfer-printing to become a common process for the fabrication of large OLED/AMOLED displays.

Experimental OLED displays using conventional photolithography techniques instead of FMMs have been demonstrated, allowing for large substrate sizes (as it eliminates the need for a mask that needs to be as large as the substrate) and good yield control.

For a high resolution display like a TV, a thin-film transistor (TFT) backplane is necessary to drive the pixels correctly. As of 2019, low-temperature polycrystalline silicon (LTPS)– TFT is widely used for commercial AMOLED displays. LTPS-TFT has variation of the performance in a display, so various compensation circuits have been reported.excimer laser used for LTPS, the AMOLED size was limited. To cope with the hurdle related to the panel size, amorphous-silicon/microcrystalline-silicon backplanes have been reported with large display prototype demonstrations.indium gallium zinc oxide (IGZO) backplane can also be used.

OLEDs can be printed onto any suitable substrate by an inkjet printer or even by screen printing,plasma displays. However, fabrication of the OLED substrate as of 2018 is costlier than that for TFT LCDs.registration — lining up the different printed layers to the required degree of accuracy.

OLED displays can be fabricated on flexible plastic substrates, leading to the possible fabrication of flexible organic light-emitting diodes for other new applications, such as roll-up displays embedded in fabrics or clothing. If a substrate like polyethylene terephthalate (PET)

OLEDs enable a greater contrast ratio and wider viewing angle compared to LCDs, because OLED pixels emit light directly. This also provides a deeper black level, since a black OLED display emits no light. Furthermore, OLED pixel colors appear correct and unshifted, even as the viewing angle approaches 90° from the normal.

LCDs filter the light emitted from a backlight, allowing a small fraction of light through. Thus, they cannot show true black. However, an inactive OLED element does not produce light or consume power, allowing true blacks.nm. The refractive value and the matching of the optical IMLs property, including the device structure parameters, also enhance the emission intensity at these thicknesses.

OLEDs also have a much faster response time than an LCD. Using response time compensation technologies, the fastest modern LCDs can reach response times as low as 1ms for their fastest color transition, and are capable of refresh frequencies as high as 240Hz. According to LG, OLED response times are up to 1,000 times faster than LCD,μs (0.01ms), which could theoretically accommodate refresh frequencies approaching 100kHz (100,000Hz). Due to their extremely fast response time, OLED displays can also be easily designed to be strobed, creating an effect similar to CRT flicker in order to avoid the sample-and-hold behavior seen on both LCDs and some OLED displays, which creates the perception of motion blur.

The biggest technical problem for OLEDs is the limited lifetime of the organic materials. One 2008 technical report on an OLED TV panel found that after 1,000hours, the blue luminance degraded by 12%, the red by 7% and the green by 8%.hours to half original brightness (five years at eight hours per day) when used for flat-panel displays. This is lower than the typical lifetime of LCD, LED or PDP technology; each rated for about 25,000–40,000hours to half brightness, depending on manufacturer and model. One major challenge for OLED displays is the formation of dark spots due to the ingress of oxygen and moisture, which degrades the organic material over time whether or not the display is powered.

Degradation occurs because of the accumulationnonradiative recombination centers and luminescence quenchers in the emissive zone. It is said that the chemical breakdown in the semiconductors occurs in four steps:

However, some manufacturers" displays aim to increase the lifespan of OLED displays, pushing their expected life past that of LCD displays by improving light outcoupling, thus achieving the same brightness at a lower drive current.cd/m2 of luminance for over 198,000hours for green OLEDs and 62,000hours for blue OLEDs.hours for red, 1,450,000hours for yellow and 400,000hours for green at an initial luminance of 1,000cd/m2.

Degradation occurs three orders of magnitude faster when exposed to moisture than when exposed to oxygen. Encapsulation can be performed by applying an epoxy adhesive with dessicant,Atomic Layer Deposition (ALD). The encapsulation process is carried out under a nitrogen environment, using UV-curable LOCA glue and the electroluminescent and electrode material deposition processes are carried out under a high vacuum. The encapsulation and material deposition processes are carried out by a single machine, after the Thin-film transistors have been applied. The transistors are applied in a process that is the same for LCDs. The electroluminescent materials can also be applied using inkjet printing.

The OLED material used to produce blue light degrades much more rapidly than the materials used to produce other colors; in other words, blue light output will decrease relative to the other colors of light. This variation in the differential color output will change the color balance of the display, and is much more noticeable than a uniform decrease in overall luminance.

Improvements to the efficiency and lifetime of blue OLEDs is vital to the success of OLEDs as replacements for LCD technology. Considerable research has been invested in developing blue OLEDs with high external quantum efficiency, as well as a deeper blue color.

Since 2012, research focuses on organic materials exhibiting thermally activated delayed fluorescence (TADF), discovered at Kyushu University OPERA and UC Santa Barbara CPOS. TADF would allow stable and high-efficiency solution processable (meaning that the organic materials are layered in solutions producing thinner layers) blue emitters, with internal quantum efficiencies reaching 100%.

Blue TADF emitters are expected to market by 2020WOLED displays with phosphorescent color filters, as well as blue OLED displays with ink-printed QD color filters.

As an emissive display technology, OLEDs rely completely upon converting electricity to light, unlike most LCDs which are to some extent reflective. E-paper leads the way in efficiency with ~ 33% ambient light reflectivity, enabling the display to be used without any internal light source. The metallic cathode in an OLED acts as a mirror, with reflectance approaching 80%, leading to poor readability in bright ambient light such as outdoors. However, with the proper application of a circular polarizer and antireflective coatings, the diffuse reflectance can be reduced to less than 0.1%. With 10,000 fc incident illumination (typical test condition for simulating outdoor illumination), that yields an approximate photopic contrast of 5:1. Advances in OLED technologies, however, enable OLEDs to become actually better than LCDs in bright sunlight. The AMOLED display in the Galaxy S5, for example, was found to outperform all LCD displays on the market in terms of power usage, brightness and reflectance.

While an OLED will consume around 40% of the power of an LCD displaying an image that is primarily black, for the majority of images it will consume 60–80% of the power of an LCD. However, an OLED can use more than 300% power to display an image with a white background, such as a document or web site.

OLEDs use pulse width modulation to show colour/brightness gradations, so even if the display is at 100% brightness, any pixel that"s, for example, 50% grey will be off for 50% of the time, making for a subtle strobe effect. The alternative way to decrease brightness would be to decrease the constant power to the OLEDs, which would result in no screen flicker, but a noticeable change in colour balance, getting worse as brightness decreases.

Almost all OLED manufacturers rely on material deposition equipment that is only made by a handful of companies,Canon Tokki, a unit of Canon Inc. Canon Tokki is reported to have a near-monopoly of the giant OLED-manufacturing vacuum machines, notable for their 100-metre (330 ft) size.Apple has relied solely on Canon Tokki in its bid to introduce its own OLED displays for the iPhones released in 2017.

OLED technology is used in commercial applications such as displays for mobile phones and portable digital media players, car radios and digital cameras among others, as well as lighting.Philips Lighting has made OLED lighting samples under the brand name "Lumiblade" available onlineNovaled AG based in Dresden, Germany, introduced a line of OLED desk lamps called "Victory" in September, 2011.

Nokia introduced OLED mobile phones including the N85 and the N86 8MP, both of which feature an AMOLED display. OLEDs have also been used in most Motorola and Samsung color cell phones, as well as some HTC, LG and Sony Ericsson models.ZEN V, the iriver clix, the Zune HD and the Sony Walkman X Series.

The Google and HTC Nexus One smartphone includes an AMOLED screen, as does HTC"s own Desire and Legend phones. However, due to supply shortages of the Samsung-produced displays, certain HTC models will use Sony"s SLCD displays in the future,Nexus S smartphone will use "Super Clear LCD" instead in some countries.

OLED displays were used in watches made by Fossil (JR-9465) and Diesel (DZ-7086). Other manufacturers of OLED panels include Anwell Technologies Limited (Hong Kong),AU Optronics (Taiwan),Chimei Innolux Corporation (Taiwan),LG (Korea),

DuPont stated in a press release in May 2010, that they can produce a 50-inch OLED TV in two minutes with a new printing technology. If this can be scaled up in terms of manufacturing, then the total cost of OLED TVs would be greatly reduced. DuPont also states that OLED TVs made with this less expensive technology can last up to 15 years if left on for a normal eight-hour day.

The use of OLEDs may be subject to patents held by Universal Display Corporation, Eastman Kodak, DuPont, General Electric, Royal Philips Electronics, numerous universities and others.

Flexible OLED displays have been used by manufacturers to create curved displays such as the Galaxy S7 Edge but they were not in devices that can be flexed by the users.

On 31 October 2018, Royole, a Chinese electronics company, unveiled the world"s first foldable screen phone featuring a flexible OLED display.Samsung announced the Samsung Galaxy Fold with a foldable OLED display from Samsung Display, its majority-owned subsidiary.MWC 2019 on 25 February 2019, Huawei announced the Huawei Mate X featuring a foldable OLED display from BOE.

The 2010s also saw the wide adoption of tracking gate-line in pixel (TGP), which moves the driving circuitry from the borders of the display to in between the display"s pixels, allowing for narrow bezels.

Textiles incorporating OLEDs are an innovation in the fashion world and pose for a way to integrate lighting to bring inert objects to a whole new level of fashion. The hope is to combine the comfort and low cost properties of textile with the OLEDs properties of illumination and low energy consumption. Although this scenario of illuminated clothing is highly plausible, challenges are still a road block. Some issues include: the lifetime of the OLED, rigidness of flexible foil substrates, and the lack of research in making more fabric like photonic textiles.

The number of automakers using OLEDs is still rare and limited to the high-end of the market. For example, the 2010 Lexus RX features an OLED display instead of a thin film transistor (TFT-LCD) display.

A Japanese manufacturer Pioneer Electronic Corporation produced the first car stereos with a monochrome OLED display, which was also the world"s first OLED product.Yazaki,Hyundai Sonata and Kia Soul EV use a 3.5-inch white PMOLED display.

By 2004, Samsung Display, a subsidiary of South Korea"s largest conglomerate and a former Samsung-NEC joint venture