flexible transparent lcd display free sample

Instead of a few hundred thousand thermostats, gas pumps and credit card terminals that use monochrome character or graphic LCDs being the driving market for small displays, we now have giant companies turning out hundreds of millions of cell phones, each with an incredible display that was barely thinkable only 20 years ago.

The “small” production volumes and very long product lifecycle of typical embedded applications often preclude these leading-edge displays from being used. The most incredible high-density AMOLED (Active Matrix OLED) display may only be produced for 2-3 years before the next generation phone, with its next-generation display, makes the old design obsolete.

As a design engineer for embedded systems, you want to include a beautiful display, but you know the risk of having a critical component of your system become impossible to get — forcing a redesign and stopping production while a new solution is found.

Where is the balance between a relatively boring display that has a very stable supply, and the latest cutting-edge display that will not be available at the time you hit your first production?

The questions we ask are: Is the supply of these new displays stable? Are the manufacturers of these displays stable? Is this display an example of a moving target that will become completely replaced by the next generation in a year or two?

We are happy to say that we are adding both flexible and transparent displays to the Crystalfontz lineup. Please see the top of this post for the latest additions.

At Crystalfontz, we strive to keep each of our displays available indefinitely. The first CFA-634 LCDs first shipped in 1999 and the CFA-634 is still available today — keeping backward compatibility even as we upgrade technology and add features.

When we provide a display for sale, it is our express goal to make sure that a design using our display will not be left out in the cold. Our goal is to make sure that the original display is available, or when that is impossible we work hard to make sure a replacement is available that has the minimum possible impact on your design and production.

OLED technology enables thin, efficient and bright displays and lighting panels. OLEDs are currently used in many mobile devices, some TVs and lighting fixtures. OLED displays offer a better image quality compared to LCD or Plasma displays - and can also be made flexible and transparent.

Several companies develop transparent OLED (also referred to as T-OLED) technologies. While there"s no inherent technology barrier towards transparent OLED displays, finding actual applications for such displays is not easy.

As of 2021, LG Display is producing 55-inch transparent OLED panels (used mostly in signage and commercial settings) while other companies produce small (around 1-2 inch in size) transparent PMOLED display. In April 2013 we posted a review of Futaba"s 2" 160x128 transparent PMOLED panel - which could be an interesting read even if this specific display is no longer in production.

OLED technology can be used to make lighting panels - these are thin, area-lit and efficient lighting panels, that can be made transparent. Unlike displays, transparent OLED lighting panels have more immediate applications (embedded in windows, for example). In April 2012 we posted our hands-on review with a transparent Tabola OLED lighting panel sample. As the OLED lighting market in general is still at an early stage, we do not see actual adoption and production of transparent OLED lighting.

The report package also provides a complete list of transparent OLED developers and makers and their current (and future) products, and a lot more. Read more here!

Transparent display technology surrounds us, even if we aren’t aware of it. In this article we look at transparent head-up displays, LCDs, OLEDs and transparent electroluminescent technology and delve into the pros and cons of the four main transparent technology displays.

However, if you think this is new technology, think again. While most transparent technology has come to the fore since the millennium, it was being used as far back as the mid-20th century.

In this article, we’re looking at four types of transparent tech which include typical projection head-up displays (HUDs), LCDs, OLEDs, and transparent electroluminescent displays (TASEL). We’ll look at the pros and cons of each and show you how transparent display technology plays an essential part in our working lives and free time. An explanatory

Of our four featured displays, we start with the oldest, HUDs. The HUD we’re referring to here is a typical projection head-up display. These use a projection system to project images onto a piece of glass in front of the viewer.A typical HUDcontains three primary components: a projector, a combiner, and a video generation computer.

The first steps into creating transparent head-up displays can be traced back as far as 1937. However, it wasn’t until the 1950s, following perfections to the technology by the US and British Royal Navies, UK Ministry of Defence and, finally, the Royal Aircraft Establishment in 1958, that the first true projection ‘head-up display’ was incorporated into aircraft.

There is also an emerging technology calledTASEL, which makes it possible to laminate displays in glass and show information without a projection system. However, as this a different transparent technology, we’ll mention thislaterin the article.

The most common transparent projection HUD is a display composed by a piece of flat glass used to project images in front of the pilot. This allows the pilot to keep their head up (hence the name ‘head-up display’) so they’re not distracted by looking down at their control panel for information during flight.

Why have we included LCDs as a transparent display when, at first glance, they’re not truly transparent? In fact, we’re only able to see the information on our monitors, such as laptops, with the introduction of a backlight and a reflector shield.

Take these away and we see true transparency of the LCD display - which is something Samsung did in 2012 with the production of theirSamsung Transparent Smart Window.

However, to see the information, it needed the reintroduction of a backlight at all times to view it and, although this technology has been used to display products in stores, the need for constant light at the rear of the display makes its use limited outside of a strictly controlled environment.

LCDs are also one of the most popular screens on the market and this rise occurred early in the 21st century when liquid-crystal-display sets rocketed in popularity. In 2007, LCDs eclipsed sales of competing technologies like plasma, cathode ray tube, and rear-projection TVs.

They were thinner and lighter, easier to scale. And for the manufacturers, the cost of production was lower, so it’s easy to see how LCD displays quickly became a favorite with manufacturers and consumers.

Organic light-emitting diode displays, orOLEDsfor short, are a step up from LCDs when it comes to transparent technology. For starters, unlike LCDs, OLEDs do not require the use of a backlight or any other filters due to the use of pixels which produce their own light.

This means they’re thinner and lighter and have higher levels of brightness which is why they’re used to create displays in smartphones, tablets, computer/laptop monitors and portable games consoles.

Lumineq’s Transparent Electroluminescent displays consist of a glass panel with a luminescent phosphorous layer and a circuit board. The circuit board contains the drive and controls which are connected directly to the glass panel making the panel light up.

As it’s an inorganic display with solid-state design, it’s unaffected by environmental changes, meaning it will withstand extreme temperatures (high or low), humidity, moisture, vibration and shock - none of which affects its response time.

The transparent electroluminescent displays are good solutions for transportation vehicles such as cars, buses, trucks, trains, trams, boats, and airplanes because they can be laminated in glass and turn windows/windshields into information and functional displays.

It’s viewable from all angles, is visible in all types of weather conditions and is theonlytransparent display capable of working in the most extreme environments, from the freezing temperatures of the Arctic winter to the blistering heat of a desert summer.

However, due to the limitation of monochromatic images, transparent electroluminescent displays shouldn’t be used as entertainment screens in vehicles - they should be used to display only the most critical information in the eye-line of the driver without distractions.

This comparison of different transparent display technologies is conducted by the Ph.D. reseracher Jose Rosa for theImmerSAFE project. The project stands for "IMMERSIVE VISUAL TECHNOLOGIES FOR SAFETY-CRITICAL APPLICATIONS".

Each transparent display has its positives and negatives, and they’re all fantastic ways to showcase transparent display technology at its best when applied in areas which suit their purpose perfectly.

HUDs are ideal for planes and cars, however, Lumineq’s in-glass displays rival HUDs, doing an equally good job with the bonus of it using less space and costing less to implement too.

Lumineq’s transparent electroluminescent displays are ideal in transportation vehicles, heavy machinery, such as tractors, and optical devices, like range-finders and night-vision goggles.

To read how in-glass technology is making giant strides in optical devices, read our post ‘Bring augmented reality to optical devices with transparent displays’, or to find out more about Lumineq"s transparent electroluminescent technology,contact ustoday.

As exciting as these unlimited possibilities are, they also create a new need for understanding and embracing the benefits of see-through displays. The eBook from below will provide you with ideas, inspiration, basic guidelines and industry examples for designing transparent displays for vehicles – from cars, tractors, and ships to aircraft.

A large transparent liquid crystal display (LCD) prototype with ultrahigh transmittance and good see-through property is demonstrated in this paper. The transmittance reaches more than 20% by introducing the RGBW pixel arrangement, a thin color filter process, a large aperture ratio design, as well as antireflective polarizer film. The see-through image quality is also greatly improved by suppressing the blurring by using domain reduction pixel design. All these approaches are applicable for large LCD panel products, and we expect broad applications of large transparent LCDs in the near future.

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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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Water can instantly damage the organic materials of the displays. Therefore, improved sealing processes are important for practical manufacturing. Water damage especially may limit the longevity of more flexible displays.

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),

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, was the world"s largest OLED manufacturer, producing 40% of the OLED displays made in the world,AMOLED market.million out of the total $475million revenues in the global OLED market in 2006.

In October 2008, Samsung showcased the world"s thinnest OLED display, also the first to be "flappable" and bendable.mm (thinner than paper), yet a Samsung staff member said that it is "technically possible to make the panel thinner".cd/m2. The colour reproduction range is 100% of the NTSC standard.

At the Consumer Electronics Show (CES) in January 2010, Samsung demonstrated a laptop computer with a large, transparent OLED display featuring up to 40% transparency

Samsung"s 2010 AMOLED smartphones used their Super AMOLED trademark, with the Samsung Wave S8500 and Samsung i9000 Galaxy S being launched in June 2010. In January 2011, Samsung announced their Super AMOLED Plus displays, which offer several advances over the older Super AMOLED displays: real stripe matrix (50% more sub pixels), thinner form factor, brighter image and an 18% reduction in energy consumption.

In May 2007, Sony publicly unveiled a video of a 2.5-inch (6.4 cm) flexible OLED screen which is only 0.3 millimeters thick.mm thick 3.5 inches (8.9 cm) display with a resolution of 320×200 pixels and a 0.3mm thick 11-inch (28 cm) display with 960×540 pixels resolution, one-tenth the thickness of the XEL-1.

In July 2008, a Japanese government body said it would fund a joint project of leading firms, which is to develop a key technology to produce large, energy-saving organic displays. The project involves one laboratory and 10 companies including Sony Corp. NEDO said the project was aimed at developing a core technology to mass-produce 40inch or larger OLED displays in the late 2010s.

In October 2008, Sony published results of research it carried out with the Max Planck Institute over the possibility of mass-market bending displays, which could replace rigid LCDs and plasma screens. Eventually, bendable, see-through displays could be stacked to produce 3D images with much greater contrast ratios and viewing angles than existing products.

In January 2015, LG Display signed a long-term agreement with Universal Display Corporation for the supply of OLED materials and the right to use their patented OLED emitters.

On 6 January 2011, Los Angeles-based technology company Recom Group introduced the first small screen consumer application of the OLED at the Consumer Electronics Show in Las Vegas. This was a 2.8" (7cm) OLED display being used as a wearable video name tag.cm) OLED displays on a standard broadcaster"s mic flag. The video mic flag allowed video content and advertising to be shown on a broadcasters standard mic flag.

On 6 January 2016, Dell announced the Ultrasharp UP3017Q OLED monitor at the Consumer Electronics Show in Las Vegas.Hz refresh rate, 0.1 millisecond response time, and a contrast ratio of 400,000:1. The monitor was set to sell at a price of $4,999 and release in March, 2016, just a few months later. As the end of March rolled around, the monitor was not released to the market and Dell did not speak on reasons for the delay. Reports suggested that Dell canceled the monitor as the company was unhappy with the image quality of the OLED panel, especially the amount of color drift that it displayed when you viewed the monitor from the sides.Hz refresh rate and a contrast ratio of 1,000,000:1. As of June, 2017, the monitor is no longer available to purchase from Dell"s website.

Apple began using OLED panels in its watches in 2015 and in its laptops in 2016 with the introduction of an OLED touchbar to the MacBook Pro.iPhone X with their own optimized OLED display licensed from Universal Display Corporation.iPhone XS and iPhone XS Max, and iPhone 11 Pro and iPhone 11 Pro Max.

A third model of Nintendo"s Switch, a hybrid gaming system, features an OLED panel in replacement of its current LCD panel. Announced in the summer of 2021, it was released on 8 October 2021.

On 18 October 2018, Samsung showed of their research roadmap at their 2018 Samsung OLED Forum. This included Fingerprint on Display (FoD), Under Panel Sensor (UPS), Haptic on Display (HoD) and Sound on Display (SoD).

Various venders are also researching cameras under OLEDs (Under Display Cameras). According to IHS Markit Huawei has partnered with BOE, Oppo with China Star Optoelectronics Technology (CSOT), Xiaomi with Visionox.

In 2020, researchers at the Queensland University of Technology (QUT) proposed using human hair which is a source of carbon and nitrogen to create OLED displays.

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TransPrint is a method for fabricating flexible, transparent free-form displays based on electrochromism. Using screen-printing or inkjet printing of electrochromic ink, plus a straightforward assembly process, TransPrint enables rapid prototyping of displays by nonexperts. The displays are nonlight-emissive and only require power to switch state and support the integration of capacitive touch sensing for interactivity. We present instructions and best practices on how to design and assemble the displays and discuss the benefits and shortcomings of the TransPrint approach. To demonstrate the broad applicability of the approach, we present six application prototypes.

Decreasing price and the widespread adoption of mobile and wearable devices have driven a dramatic increase in the amount of digital displays we encounter in our everyday lives. However, our environment still contains far more nondigital printed graphics, such as labels, signs, posters, and books, than digital displays. Static text and graphics printed on paper and other objects have been one of our major information sources for many years and will continue to be so. While, in many applications, digital displays aim to emulate the properties of printed graphics, they are limited to a rigid flat rectangular form factor. This limitation restricts the possibilities to seamlessly integrate such displays into our surroundings.

Recently, the field of printed electronics has developed to the point at which thin and deformable interactive prototypes can be created at low cost, e.g., as design prototypes [1–3]. Prior work has focused on extending printing methods to create interactive materials such as flexible touch sensors, thin film displays, and even haptic feedback [4–7]. Especially, printed electronics displays have the potential to overcome the limitations of current digital display technologies, enabling more interactivity and new form-factors. Moving away from the square pixel-based architecture, which is dominant in today’s display technologies, has been highlighted as a key factor to deliver truly ubiquitous technologies [8].

In this paper, we present TransPrint, an adaptable method that enables the production of flexible, transparent displays in highly customizable shapes by the maker community and other nonexperts (see Figure 1). TransPrint is based on electrochromism (EC), i.e., the property of materials to reversibly switch their optical properties, e.g., colour, through electrochemical oxidization. For TransPrint, this switch is between near-transparency and a dark blue opaque colour.

One of the key traits of displays based on electrochromic systems is that they are nonlight-emissive. This distinguishes them from LED and electroluminescence (EL) based displays [4, 6]. Given the negative impact of artificial light on human sleep patterns [9], this property is particularly beneficial for ubiquitous always-on displays, e.g., as part of Internet of Things (IoT) solutions. Together, the properties of TransPrint displays enable smart solutions that are embedded to the existing objects and surfaces of our environment, fulfilling Mark Weiser’s vision of technologies that “weave themselves into the fabric of everyday life” [10].

While EC-based displays have been well established and most characteristics of the different materials have been well investigated in the past, constructing these displays usually required laboratory settings [11]. With TransPrint we present a method that allows nonexperts to produce EC-based displays with commercially available materials. We present two ways of printing such displays using either screen-printing or inkjet printing. Both methods are rapid and inexpensive and only require a limited amount of hardware and technical knowledge. We show how to integrate these printed displays with static printed elements as well as new application scenarios stemming from the unique traits of TransPrint displays. Furthermore, we discuss how support for capacitive touch input can be easily incorporated. With this we hope to enable the community to adapt such displays and embed them in future research, e.g., in the realm of printed electronics for interaction.

In this paper, we firstly discuss related work in the fields of printed electronics and displays, focusing on electrochromic systems and transparent displays. We then provide background on the operation of electrochromic displays in general and describe the TransPrint approach to design, print, and assemble displays. Following this, we present an analysis of the key characteristics of the created displays. Finally, we present a set of application cases that demonstrate the possibilities of TransPrint displays.

Building on these previous approaches, TransPrint employs inkjet and screen-printing in the creation of our displays and aims to enable the combination of printed EC displays with other printed electronics prototyping techniques, hence, enabling easy integration into wider printed electronics prototyping pipeline.

A major distinction when it comes to thin film display technologies is whether the display is pixel-addressable such as OLED and E-Ink, or a graphical segment-based display in which only predefined shapes can be switched. Although the second category offers less visual dynamicity, it provides advantage in other areas, such as ease of fabrication and possibility of creating displays in a variety of shapes and forms. Common technologies to realize thin film displays are, e.g., ultraviolet [26], thermochromism [27, 28], electroluminescence (EL) [4, 6, 29], and electrochromism (EC) [4, 30, 31], each having relative advantages and disadvantages. Ultraviolet-based displays require an additional light source and can suffer from low visibility in daylight conditions. Thermochromism is hard to control, due to the need for exact temperature control and the potential influence of ambient temperature. EC and EL displays are easy to fabricate at low cost and are flexible, robust, and low-power consuming. EL displays have a relatively long lifetime of up to 50,000 hours and, in comparison to EC, have faster switching times [6], making EL suitable for lighting applications [6, 32]. (Switching time here refers to the time it takes to switch from on state, e.g., an off state where nothing is shown to another state where something else is shown.) Different techniques have been proposed for the production of EL displays, such as cutting segments from a larger EC film [33], and screen- and inkjet printing the substrate layers [6]. Olberding et al. demonstrated the possibilities of such displays with a design space that included different materials as well as a variety of application cases [6]. Additionally, screen-printed EL displays can be integrated with textiles [34]. Klamka and Dachselt extended the EL design space with their exploration into the possibilities of added pen interaction [4]. EC-based displays have several promising properties; for example, they can hold their display content for an amount of time without a battery, like e-ink displays. As with e-ink displays, they do not emit any light themselves and they have a comparably slow switching time between states. Previous work on EC displays investigated the capabilities for mass-manufacturing [35], manual manufacturing processes [30], and even developed multilayered colour displays [31]. One of the main application cases for electrochromism so far is smart windows [36–38], while, more recently, other HCI applications have been explored. Klamka and Dachselt used an EC-based 8-segment display in their IllumiPaper prototype and Vyas et al. used an EC-based display that changed opacity with the increasing dust level of a vacuum cleaner [4, 39]. With TransPrint, we extend this line of work by presenting a fabrication process that enables nonexperts to produce such displays and demonstrating the capabilities of EC-based displays for a wider range of mobile and wearable UbiComp and HCI prototypes. Compared to previous work, we specifically provide detailed instruction on the design, printing, and assembly processes for transparent EC displays, which are based on commercially available materials and can be fabricated in nonlaboratory settings with simple prototyping equipment.

Electrochromism is the capability of some materials to reversibly change colour stimulated by redox reactions. This means that EC materials can change their optical absorption characteristics or colour when an electrical voltage is applied. A variety of different materials exist that can switch between different colour combinations and intensities. For TransPrint we are using the PEDOT:PSS (the chemical name poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) mixture for printing, which can change its colour from nearly transparent to a darker blue. The PEDOT:PSS mixture exhibits EC properties because it is electrochemically active which makes it suitable as electrodes in EC displays and operates at low voltages (1-5 volt). Additionally it takes few seconds (< 3s) and requires low current draws (< 3mA) to switch a 5x5cm display fabricated with PEDOT:PSS. However, one thing to note is switch time and current draw heavily depends on size and graphics design (amount of PEDOT:PSS used).

EC displays have several characteristic properties that enable a variety of applications [11]. They exhibit open circuit memory where its state stays the same when there is no short circuit, similar to electrical batteries, and can maintain their optical state and electrical charge for extended periods of time while drawing comparably little energy. This means that once the display reaches the desired visual state, no further energy is required to maintain the state. Energy is only needed to create a state change. The optical absorption (or in practice the strength of colouration) can be calibrated and set to any level between the states of minimum and maximum absorption; see Figure 2. Compared to EL displays, the optical state transitions of EC displays are slow, typically lasting a few seconds, depending on physical dimensions and used materials. While some EC materials can take tens of minutes to switch, the PEDOT:PSS employed for TransPrint switches in less than 10 seconds even at A4 size prints. EC displays do not emit any light; they only change the amount of light they absorb. Given that the increasing amount of artificial light in our daily life—especially from digital displays—has been shown to lead to disrupted sleep patterns and increased sleep deficiency [9], the nonlight-emissivity of EC displays presents an opportunity for more ubiquitous display deployment.

To date, EC technology has predominantly been used in windows and smart glass, enabling dynamic change of optical and thermal characteristics [36–38]. This is because the change of the absorption happens on an atomic level and therefore allows EC windows to switch without visible haze [40]. Recent advances have shown EC to be usable as an anticounterfeiting method by applying electrochromic materials to paper [41]. While EC is a rather old and well-established technology in the field of organic chemistry, it has so far mostly been neglected for HCI research [4, 38, 39]. One possible factor for this is the problem of fabricating such displays, which we try to overcome with the TransPrint method.

A functioning EC display is composed of the following components: two conductors (electrodes) each connected to a field of EC material or ‘ink’, and electrolyte which separates the two fields of EC material (see Figure 3). The conductors create an electrical circuit by allowing electrons and ions to move when an electrical current is applied through the EC material. The electrolyte is a gel substance with electrically conductive properties and is responsible for the ion exchange between the two fields of EC ink when a voltage is applied at the conductors. Insertion or extraction of ions into the EC ink changes the optical characteristics through reduction and oxidization, and as little as 1V is sufficient for this change to occur. An EC system needs two fields of EC ink that are connected to two different conductors so that an exchange of ions from one field to the other can happen when a voltage is applied. One field will be oxidized while the other is reduced, and vice versa when the polarity of the voltage is reversed. Visually, this redox causes one EC field to become transparent while the other gains colour. Alternatively, one of the EC ink fields can also be replaced by any other ion storage material that does not exhibit colour change on redox, as shown in Figure 3.

While theoretically not needed for functionality, the display components need to be contained by elements that will insulate and protect them. Thus, top and bottom substrates are required. To be able to observe the visual change, at least the upper substrate should be transparent. Typically, glass has been used, but more recently, polymer-based plastics, e.g., polyethylene terephthalate (PET) and polycarbonate (PC), have been employed as well. In some implementations, the lower substrates can even be replaced with paper [42].

In this section, we present the design and fabrication process of TransPrint displays, which are transparent, flexible EC displays. This includes two alternative structures or stack designs, vertical and coplanar (see Figure 4), a detailed description of the fabrication process using screen-printing and inkjet printing as well as design considerations.

Firstly, TransPrint displays can be produced in two different ways: either a vertical or a coplanar stack of the different elements. In the vertical stack all elements are stacked vertically, meaning both electrodes with EC ink are on top of each other divided by the electrolyte (compare Figure 4 (left)). So that the ions would flow from the top layer EC ink through the electrolyte to the bottom layer EC ink or vice versa (when the polarity is switched). For the coplanar stack both EC ink fields are on the same layer with two separated electrodes (compare Figure 4 (right)). This means that the ions move from one of the EC ink fields to the other through the electrolyte. The main difference between these two construction methods is that in the vertical stack the ink fields, e.g., can overlap while in the coplanar stack they must be next to each other.

For TransPrint we selected to use transparent PET film as the substrates onto which displays are constructed. In the vertical stack configuration, one EC ink field is printed on both substrate layers, whereas in the coplanar stack, both EC ink fields are printed on a single substrate. In both cases the two EC ink fields each have their own conductor and are connected only by the electrolyte layer. The EC ink used in TransPrint displays is itself conductive; thus it is only required to configure the conductors to connect to the edges of the EC ink fields. However, to reduce potential design limitations and ensure consistent switching performance, in TransPrint we utilize substrates coated with a conductive Indium Tin Oxide (ITO) layer which is one of the most commonly used transparent conductors and is also used as the conductor on smartphone touch panels.

Thus, TransPrint utilizes PET film precoated with ITO (PET-ITO) as substrates. For the vertical stack, both base and top layer are PET-ITO whereas for the coplanar structure PET-ITO is used for the base layer and noncoated PET for the upper layer. When using precoated PET-ITO where the whole piece is one conductor (e.g., the Adafruit ITO Coated PET (https://www.adafruit.com/product/1309) with a thickness of 175μm) for the coplanar stack, electrical separation of the two ink fields must be ensured, e.g., by scratching away the ITO coating from the PET to create a gap. Graphical display designs can be printed directly onto the ITO side of the PET-ITO using either screen- or inkjet printing. The PET-ITO material used is a thin film, which can easily be cut to different shapes, increasing the options for customization and flexibility of the displays. To prevent electrical short circuits between the top and bottom layers and to provide a container for the electrolyte, the PET-ITO substrate layers must be held apart.

In TransPrint this separation is created using double-sided adhesive sheets in which spaces have been cut out around the ink printed area, specifically 3M 9495 LE 300LSE, with a thickness of 170μm (see Figure 5). The amount of electrolyte required is calculated as the cubic volume of the container that is created between the two substrates and the spacer. For example, a display with a 5x5cm area using the previously mentioned adhesive sheets give the container a height of 170μm and therefore require 0.425mL of electrolyte (5cm x 5cm x 0.017cm = 0.425 cm3 = 0.425ml). This means that the average amount of needed electrolyte is dependent on the size of the display.

Figure 2 shows the transition between the two maximum states of a vertical stack EC display, caused by the reversal of the polarity of the voltage applied across the display conductors. For this 5x5cm display the full transition takes approximately 2.5s. Applying power to the display for shorter times will place the display in an intermediate state where the maximum opacity is not reached. Switching time and required voltage are dependent on the EC design, size, and used ink and electrolyte. For the Ynvisible EC-SC ink a maximum voltage of 3V is recommended; however the ITO layer on the PET-ITO will degrade if a voltage of more than 1.5V is used, which in turn sets the maximum voltage for driving the display. Given these low voltage levels, the displays can easily be controlled using, e.g., an Arduino microcontroller, and could be even activated using wireless energy sources such as NFC, as demonstrated by Dierk et al. [44]. Furthermore, the active operation temperature of these displays’ ranges from -100°C to +100°C and they continue to be functional after structural damage (e.g., a corner cut off) if the two conductors are not creating a short circuit. The displays are also bendable up to 7.5mm radius (see Figure 1) while remaining functional. The bend radius is limited by the fact that the ITO layer on the PET-ITO will break with a lower radius and thus increase the resistance. This also means that the mechanical endurance of the displays when repeatedly bends is only dependent on the quality of the PET-ITO. A bend radius of 0.75cm-1cm has been shown to have no influence on the resistance of the PET-ITO [45]. However, not only the bend radius is increasing the resistance of the PET-ITO but also repetitive bending as it leads to microcracks [46, 47]. Given results presented by Li and Lin it is expected that after ca. 300 bends with 17.3N strain the PET-ITO would reach a level were a significant increase in switching time would be visible and after 2000 bends being most likely be unusable due to the number of microcracks [47].

Furthermore, it should be noted that the printing of TransPrint displays does not require a completely dust free work environment. Although any dust particles etc. that made it onto the materials during the construction process will be visible on the display, they will not impede the display’s functionality. Nevertheless, it is advised to work in an as clean environment as possible and use gloves through the whole procedure to not leave fingerprints on the display.

When designing the graphics for a TransPrint display several factors should be considered. Vertical stack structures have two layers overlaid on each other, allowing a large degree of creativity in how the finished display will look. In the coplanar structure, the EC fields should be next to each other, enabling the ions to move from one field to the other, placing more restrictions on the design. To partly address this limitation, opaque masks may be placed on top of the display; e.g., Klamka and Dachselt used a coplanar 8-segment EC display for their work, in which each segment in the display consisted of a pair of EC fields which were used [4]. In this case, one field was the visible segment of the 8-segment display, while the other served as a masked counterpart to complete the redox reaction.

If screen-printing is used, the frame count and emulsion determine the minimum size of both trace width and detail size; however there is no limitation for how big a trace or feature can be. The same applies when vinyl cutting is used to create a stencil; the accuracy of the vinyl cutter used must be sufficient for the level of detail in the design. Once the graphics have been developed, the design has to be finalized for print which requires adding registration lines for the spacer material (double-sided tape) and connections for the electrodes (see Figure 5). This step is especially important when designing for the vertical stack structure, as the conductive leads should be offset to avoid short