How have the screens evolved? A guide to display technology

History of image display technology

The history of screens is a story of the evolution of image display technology, which began more than a century ago and continues to evolve at a rapid pace:

Mechanical and projection-based screens (19th century – early 20th century)

The first “screens” were not yet true image display devices. Instead, they served as surfaces for projecting light from devices such as the laterna magica (17th century) or early 20th-century film projectors. Cinemas used canvas or painted screens to display moving images.

• 1895 – The Lumière brothers present the first public film screening using a projector and a projection screen.
• 1925 – John Logie Baird demonstrates the first television screen, still in a mechanical version. The image was monochrome, composed of 30 lines, and refreshed at 5 frames per second.
• At the same time, Vladimir Zworykin and Philo Farnsworth began working on electronic television, which revolutionized display technology by replacing mechanical television systems. Zworykin invented the iconoscope (the first practical TV camera), while Farnsworth developed the first fully electronic TV set.

Cathode Ray Tube (CRT) screens (1920–2000)

A breakthrough occurred with the invention of the Cathode Ray Tube (CRT). This technology dominated television and computer monitors for more than 70 years. CRT screens functioned by firing electron beams at a phosphor coating, causing pixels to glow.

• 1927 – Philo Farnsworth develops electronic television using a CRT screen.
• 1939 – The first large-scale demonstrations of CRT televisions took place at the World’s Fair in New York.
• 1954 – The first color CRT screen was introduced.

How does a CRT screen work?

1. An electron gun located at the back of the CRT emits a beam of electrons.
2. Deflection coils steer the electron beam, directing it to the appropriate points on the screen.
3. A phosphor coating covers the inside of the screen; when an electron beam strikes it, light is emitted.
4. A color screen (RGB) consists of three layers of phosphors (red, green, and blue), which, when mixed, create a full range of colors.
5. A shadow mask or aperture grid precisely directs electrons to the correct subpixels.

The image is generated by rapidly scanning lines from top to bottom of the screen—a process that occurs many times per second, creating the impression of a smooth image.

Advantages of CRT Technology:

• Excellent color reproduction and smooth motion.
• Low production cost in mass manufacturing.
• No ghosting due to fast refresh rate, though motion blur may still occur due to the sample-and-hold effect and phosphor afterimages.

Disadvantages of CRT Technology:

• Large size and heavy weight.
• Limited resolution and poor visibility in bright environments.
• High power consumption, using more energy than LCD or LED.
• Image flickering at low refresh rates (<75 Hz) can cause eye strain.

Modern display technologies

Nowadays, the screen market is extremely diverse, depending on the application in the design of electronic devices, designers must choose the appropriate screen technology, taking into account such factors as power consumption, contrast, viewing angles and response time. Before going into a detailed description of today’s technologies, it is worth looking at their main areas of application:

• Smartphones, tablets, and laptops – OLED, LCD, flexible OLED
• Computer monitors and TVs – LCD, OLED, QD-OLED, MicroLED
• VR and AR devices – microOLED, MicroLED
• Transparent displays and HUDs – OLED, MicroLED
• Digital advertising and large-format displays – LCD, MicroLED
• E-book readers and low-power devices – E-Ink

Modern display technologies such as OLED, MicroLED, and QD-OLED provide better image quality, deeper contrast, and energy-efficient solutions. By implementing modern solutions in electronics design, technology companies can optimize display performance for end users. 

The Revolution of LCD Technology (1970s – Present Day)

LCD (Liquid Crystal Display) technology marked the beginning of the flat-panel display era. Initially used in calculators and electronic watches, it gradually found its way into monitors and televisions.

• 1972 – The first LCD screen is developed, mainly used in calculators.
• 1995 – LCDs start being used in laptops.
• 1999 – Sharp introduces LCD televisions.
• 2010 – The transition from CRT to LCD had already begun in the 1990s, and by 2010, LCDs had completely replaced CRT.

Advantages of LCD Technology:

• Low power consumption.
• Thin and lightweight design.
• Higher resolution.

Disadvantages of LCD Technology:

• Limited viewing angles and lower contrast (especially in early models).
• Slower response time, which is important for fast-moving images.

Differences between TN, IPS and VA

LCD panels are divided into TN, IPS and VA types, which differ in color quality, contrast and response time. 

TN (Twisted Nematic) – Twisted nematics.

Structure and operation:

• Liquid crystal molecules at rest are twisted 90° between two electrodes.
• When a voltage is applied, the crystals straighten, which changes the transmittance of light.
• Polarization filters control how much light passes through the pixel.

The technology is fast because the crystals change position quickly and do not require large changes in orientation, achieving very low response times. On the other hand, it has poor viewing angles because the crystals are vertically aligned in a fully active state, thus changing the way light passes through at different angles. Causing color degradation and “fading” of the image.

IPS (In-Plane Switching) – In-plane switching.

Construction and operation:

• The crystals are aligned parallel to the screen surface and change their orientation in the plane (they move sideways instead of twisting).
• Uniform switching allows light to pass more evenly through each pixel.

This technology enhances colors and viewing angles. The crystals always remain parallel to the screen, so they do not change depending on the viewing angle. Light passes through more uniformly, ensuring more precise color reproduction. The IPS type is slower, however, because the movement of the crystals is more complex. Rather than simply twisting, they shift horizontally. As a result, the response time is slightly longer than that of TN panels (although modern IPS displays can compete in this regard).

VA (Vertical Alignment) – Vertical alignment.

Construction and operation:

• At rest, the crystals are aligned vertically (perpendicular to the screen surface), which blocks light and creates deeper blacks.
• When voltage is applied, the crystals tilt, allowing light to pass through.

The VA type has the best contrast because, at rest, the crystals block light completely, resulting in deep blacks and a contrast ratio of 3,000:1 or even 5,000:1 (by comparison, IPS has about 1,000:1). They do not allow unwanted light to pass through, which makes VA screens perfect for watching movies.

VA panels may suffer from ghosting because the crystals must transition from a vertical to a tilted position, a slower movement compared to IPS and TN panels. This can lead to longer response times (e.g., 4-6 ms), and in older models, a phenomenon known as ghosting can occur, where moving objects leave a visible trail.

Plasma and OLED (1990s – present day)

Plasma (PDP – Plasma Display Panel)

Plasma screens became popular in the 1990s due to their excellent color reproduction and contrast. They were especially valued for large screen sizes, but their production was costly, and their high energy consumption, along with burn-in issues, led to their gradual phase-out. A plasma screen consists of cells filled with gas, which, when energized, turns into plasma, emitting ultraviolet light. This light stimulates the phosphor to glow, producing a color image.

Advantages:

• Excellent color reproduction and contrast.
• Fast response time.

Disadvantages:

• High power consumption.
• Burn-in and reduced lifespan caused by prolonged display of static images.

OLED (Organic Light Emitting Diode)

OLED is a breakthrough technology that enables the creation of flexible and transparent displays. OLED is a type of light-emitting diode (LED) that utilizes organic semiconductors to produce light. The OLED structure is layered, consisting of very thin organic layers sandwiched between two electrodes on a transparent substrate. Typically, there are two main layers: a conductive layer (which transports holes from the anode) and an emission layer (which transports electrons from the cathode); each plays a distinct role in the luminescence process. The entire “sandwich” of layers has a total thickness of several hundred nanometers, which enables the construction of exceptionally thin and flexible displays.

The principle of OLED technology is based on electroluminescence, which is the direct emission of light under the influence of an applied voltage. When a voltage is applied to the anode and cathode in the conduction direction, electrons are injected from the cathode into the emission layer, and so-called holes (electron gaps) are injected from the anode into the conducting layer. The holes travel to the emission layer, where they recombine with electrons arriving from the cathode. The recombination of charges in the organic material causes the electron to move to a lower energy level and emit a quantum of light (photon) in the visible range.

In other words, each OLED glows on its own under the influence of current flow. Unlike traditional LCD displays, it does not require an external backlight. When the polarity is reversed (the junction is reverse-biased), recombination does not occur, and the diode does not glow. Thanks to this design, a single pixel of the OLED display is an independent source of light.

The display matrix consists of numerous microscopic OLEDs (red, green, and blue subpixels, with additional ones possible) controlled individually. Modern displays incorporate an active matrix TFT (AMOLED), enabling the addressing of millions of pixels at high refresh rates. OLEDs can be fabricated on rigid glass or flexible plastic substrates, making it possible to create curved, foldable, and even rollable screens.

OLED advantages:

• Contrast and blacks. OLED offers virtually infinite contrast; pixels can turn off completely, producing perfect blacks. In comparison, LCDs always have a backlight running, so blacks appear washed out and contrast is limited by light-permeable liquid crystals.
• Colors and image quality. Since there are no polarizing filters or backlight layers, OLEDs achieve a wider color gamut and more saturated colors than typical LCDs. The emitted colors are vivid, and the display can cover a wide palette (Wide Gamut RGB). The image on OLED is viewed as more lifelike and vibrant, especially in low-light conditions.
• Viewing angles. OLED screens maintain color fidelity even at very wide viewing angles (close to 180°). Even when viewed from extreme angles, the image does not lose contrast or undergo color inversion. The best LCD matrices (e.g., IPS) offer wide viewing angles, but OLED still outperforms them in this respect.
• Response time. OLEDs have extremely fast pixel response times. Fast pixel switching eliminates ghosting and blurring in dynamic scenes, which is crucial for gaming and high-quality video display.
• Thickness, weight, and form factor. OLED displays can be extremely thin and lightweight, as they do not require multiple layers of filters or backlighting. This allows for the creation of slim device designs. Additionally, thanks to their ability to be applied to flexible substrates, OLED screens can be curved, bendable, or even transparent. Today, prototypes of rollable OLED screens already exist.
• Energy efficiency (in dark content). Since OLEDs do not require a fixed backlight, they use less energy when displaying dark scenes. Inactive pixels do not consume power. In typical mixed usage, OLED displays can consume up to ~30% less power than LCDs. This is particularly beneficial for dark-themed interfaces or when watching videos with black bars.

Disadvantages:

• Brightness in full-field display and readability in sunlight. Although individual OLED pixels can emit very bright spot light, the overall screen brightness is sometimes lower than that of LCDs. LCDs use a powerful LED backlight that illuminates the entire screen evenly, reaching high brightness levels. However, due to thermal constraints and longevity concerns, OLEDs often need to reduce brightness when displaying large bright areas (such as full-screen white). In strong sunlight, a typical IPS LCD may be easier to read than an OLED. However, the latest AMOLED panels have significantly improved peak brightness and now perform increasingly well in bright conditions.
• Durability and burn-in. OLEDs use organic materials that degrade over time. Blue emitters, in particular, have a shorter lifespan, which leads to a gradual fading of blue subpixels. As subpixels degrade at different rates, this leads to image burn-in, where visible remnants of static interface elements (e.g., bars, logos) remain on the screen. Although modern OLEDs (especially in TVs) feature protective mechanisms such as image shifting and pixel regeneration, prolonged display of static content at high brightness can still result in permanent artifacts.
• Effect of moisture and mechanical durability. Organic OLED layers are highly sensitive to environmental factors, particularly exposure to water and oxygen. Even minor moisture infiltration through a damaged screen housing can chemically degrade the organic material, causing dead pixels or blotches. Therefore, OLED panels require effective encapsulation (airtight sealing), which adds complexity to their design. Mechanically, thin OLED layers on plastic are prone to scratching or deformation if not adequately protected by a glass cover.
• Production cost and scalability. Despite the theoretically simpler layer design, mass production of large OLED panels remains more difficult and expensive than that of LCDs. LCD technology is well-established, with factories achieving high yields and reducing unit costs for large screens. OLED, on the other hand, requires precise deposition of organic subpixel patterns (e.g., by sputtering through masks or printing), which poses a challenge for manufacturing large TV panels. While manufacturers continue to develop new production lines and refine processes, the cost of large OLEDs still exceeds that of similarly sized LCDs. In addition, some OLED solutions have been protected by patents (including those from Eastman Kodak), which has historically hindered their widespread adoption.

E-Ink, MicroLED (Years 2010 – Future)

E-Ink (electronic paper)

E-Ink (electronic ink) is a type of e-paper display based on the electrophoresis principle. The screen consists of millions of microcapsules, each about the diameter of a human hair, filled with a transparent liquid in which pigment particles—negatively charged white and positively charged black—are suspended. When an electric field of appropriate polarity is applied, particles of one color move to the top layer of the capsule, becoming visible to the observer, while particles of the opposite charge sink to the bottom. In this way, each “pixel” can switch between black and white, creating an image that closely resembles a printout on paper. Because E-Ink is a reflective display—it uses ambient light instead of emitting its own—the image is readable in daylight and looks like traditional printed text. The technology is bistable, meaning no power is required to maintain the displayed image; energy is consumed only when the screen content changes. This allows an E-Ink screen to maintain a static image for extended periods without drawing power.

Standard E-Ink displays are monochrome (black and white), but there are also color versions. This is achieved by incorporating more than two types of pigment particles. For example, E Ink Spectra™ technology utilizes a three- or four-particle system—in addition to black and white, color pigments (red, yellow) have been added, encapsulated in microcups (Microcup) instead of microcapsules. Newer generations, such as E Ink ACeP™ (Advanced Color ePaper), even contain a complete set of color particles in each pixel, enabling full-color display without requiring a color filter. Nevertheless, current color E-Ink screens display colors in less vibrant hues compared to LCD/OLED screens due to the limited intensity of the pigments.

MicroLED – Technology of the future

MicroLED is an innovative display technology based on microscopic LEDs acting as pixels. It is a type of emissive (self-luminous) screen that promises excellent image performance, including high efficiency and brightness, “infinite” contrast, and a wide color gamut. MicroLED is often considered a potential successor to current technologies (OLED, LCD), combining their advantages while minimizing their drawbacks. Despite extensive R&D efforts, microLED remains in the early stages of commercialization.

The construction of a microLED display is based on an array of miniature light-emitting diodes. A single microdiode (μLED) is on the order of tens of micrometers or less in size, making it about 100 times smaller than a standard LED. Each pixel consists of one or more self-emitting microdiodes. The operating principle of a single microLED is similar to that of conventional LEDs: applying a voltage causes the recombination of electrons and holes in a semiconductor p-n junction, accompanied by the emission of photons, which results in the diode glowing. The structure of a microLED display consists of a control layer (e.g., a matrix of TFT transistors or a CMOS chip) with micro-LEDs placed on top. Unlike LCD or OLED displays, which are manufactured as monolithic panels on large substrates, microLED screens can be assembled from modules with no visible seams, making them easily scalable to any size. This modular design, along with the absence of filter layers or backlighting, allows microLED displays to be extremely thin and free of bezels between segments. Each pixel glows independently. MicroLED technology also enables the creation of displays on flexible or transparent substrates (similar to OLED), as demonstrated in prototypes.

MicroLED applications:

• Premium televisions.
• Large advertising displays.

MicroLED advantages:

• High brightness. Individual microLEDs can reach brightness levels exceeding 1,000,000 cd/m² (nits). This ensures that images remain legible even in strong outdoor lighting.
• Contrast and blacks. Like OLED, microLED technology is emissive, meaning that pixels can be completely turned off. This allows for perfectly deep blacks and virtually infinite contrast. Each microLED glows independently, ensuring deep blacks without light leakage.
• Energy efficiency. MicroLED displays can be more energy efficient than LCDs and OLEDs in typical applications.
• Long life, no burn-in. The use of inorganic materials (e.g., GaN) translates into much longer pixel life than in OLEDs, where organic diodes degrade over time. MicroLEDs are not subject to burn-in effects, even when static elements are displayed for long periods of time.
• Ultra-fast response time. The μLED can change state almost instantly. The response time of microLEDs is measured in nanoseconds. The speed of pixel lighting/quenching also eliminates ghosting and enables extremely high frame rates.
• Flexibility and transparency. The microLED design can be adapted to unusual forms. Flexible microLED displays (e.g., on bendable foil) are already being demonstrated, along with transparent panels where micropixels are embedded in a transparent substrate. This enables applications in flexible wearable electronics, curved screens, and transparent head-up displays. OLEDs also offer such possibilities, but microLEDs have the advantage of not requiring airtight encapsulation against moisture and oxygen (inorganic diodes are more resistant), which simplifies flexible designs.

MicroLED disadvantages:

• Very high production costs. The biggest problem with microLEDs is manufacturing costs, far exceeding those of LCDs and OLEDs. The processes for assembling millions of microdiodes are complex and time-consuming, resulting in low yields and an astronomical price for finished displays. Currently, the extremely high cost is a serious barrier to this technology entering mainstream devices.
• Technological immaturity. Unlike refined, mass-produced LCDs and OLEDs, microLED technology is still in the early stages of development. The lack of established, scalable manufacturing processes results in low production capacity and limited availability. Most of the microLED screens available are still prototypes or demonstration units rather than widely available consumer products. For example, in 2024, LG and Samsung Display decided to scale back investments in microLEDs due to their immaturity and high costs.
• Resolution scaling difficulties. Current microLED manufacturing processes are well-suited for small screens (e.g., AR micro-displays) or large pixels (large-format displays with relatively low PPI). As a result, OLEDs and LCDs currently hold the advantage in achieving high resolution in small devices, as microLEDs have yet to reach such miniaturization at an acceptable cost.
• Micro energy challenges. Paradoxically, while microLEDs promise higher efficiency, current prototypes can draw a lot of power. IDTechEx research indicates that the energy efficiency of tiny LEDs is limited. The reasons include losses at microscopic junctions, non-ideal luminescence of extremely small structures, and the need for very high brightness. As a result, potential energy savings may decrease. However, it should be noted that these are challenges specific to prototypes. In the long run, microLEDs should consume less power than competing displays, provided they are properly optimized.

Trends and forecasts for the future

Flexible and foldable OLEDs

There are already many smartphones on the market with flexible displays, and the technology has also made its way to laptops and tablets. Some models feature a single large foldable screen, such as the Lenovo ThinkPad X1 Fold (13-16″ OLED foldable screen with Windows) and the ASUS Zenbook 17 Fold OLED (17″ screen that folds in half). This allows the device to function as a tablet or small laptop when folded, and as a full-size display when unfolded.

Stretchable displays

A more futuristic advancement is stretchable OLED/LED technology, which allows screens to change their dimensions. Such displays are currently in the prototype stage. For example, in 2024, LG Display presented a 12-inch flexible microLED panel that can be stretched to 18 inches (a 50% increase). The panel has around 100 ppi and a full RGB gamut, and thanks to new materials and interconnection systems, it can withstand repeated stretching (over 10,000 cycles) without damage.

In the early stages, foldable OLEDs struggled with durability issues (e.g., creases, scratches). However, the latest models have improved, with manufacturers now using ultra-thin UTG (Ultra-Thin Glass) instead of plastic as a protective screen layer, making displays more durable and reducing the visibility of the central crease. At the same time, designers have refined hinge mechanisms, such as the water-drop hinge developed by Oppo, Samsung, and Motorola, which folds the screen into a gentle arc, improving structural durability and reducing matrix stress.

​Transparent displays

Transparent OLED (TOLED) and LCD displays have existed for years, but they remain a niche offering. LG Display, for instance, produces large transparent OLED panels ranging from approximately 30 to 77 inches, mainly for commercial applications. The first consumer TVs with a transparent screen have also appeared, such as the Xiaomi Mi TV Lux Transparent Edition (55” OLED) introduced in China in 2020, as well as limited edition models from Panasonic. Currently, transparent OLEDs are not widely used in homes, but they can be found in public spaces. Transparent screens are employed wherever there is a need to display an image on a glass surface without obstructing the view.

They are used in digital signage, such as interactive storefronts in shops and museums that showcase product information. Panels of this type have also been tested in cars.A notable innovation is the Lenovo ThinkBook Transparent Display, a laptop prototype featuring a transparent 17.3” OLED screen, unveiled at CES 2024.

Mimo swojego “wow-effect” przezroczyste ekrany zmagają się z licznymi ograniczeniami. Po pierwsze, niski kontrast i jaskrawość, ponieważ nie mają czarnego tła, czerń jest w zasadzie przezroczysta, a wyświetlane kolory nakładają się na to, co za ekranem. W jasnym otoczeniu obraz bywa słabo widoczny, chyba że zastosujemy specjalne szkło przyciemniające tło. Po drugie, kwestie prywatności – standardowy przezroczysty OLED emituje obraz w obie strony, więc treści są widoczne także od tyłu ekranu​.Inne wyzwania to trwałość i koszt. Przezroczyste panele OLED są drogie w produkcji i stosunkowo delikatne (muszą być na cienkim szkle lub plastiku, aby były przeźroczyste). Nic dziwnego, że eksperci widzą w tej gałęzi raczej ciekawostkę niż przyszłość mainstreamu, prawdopodobnie transparentne OLED-y/microLED-y pozostaną niszą ze względu na ograniczoną praktyczność​. Mimo to nisza ta może rosnąć w specyficznych zastosowaniach, jak inteligentne witryny sklepowe, kokpity AR w pojazdach, okulary AR itp., gdzie przezroczysty wyświetlacz daje unikalne możliwości interakcji z otoczeniem.

Ekrany VR i AR

Urządzenia rzeczywistości wirtualnej (VR) i rozszerzonej (AR) korzystają z różnych typów ekranów dostosowanych do specyfiki użycia. W typowych goglach VR (oraz w tzw. passthrough AR, gdzie obraz z kamer jest wyświetlany na ekranie gogli) dominują szybkie panele LCD TFT lub OLED (AMOLED) o wysokim odświeżaniu​. 

Jeśli chodzi o samą technologię ekranów, to najbardziej rewolucyjnie zapowiadają się microLEDy w AR, gdy uda się je zaimplementować masowo, pozwolą na zbudowanie okularów AR o wyglądzie zwykłych okularów (bo potrzebny będzie tylko cienki, przezroczysty wyświetlacz w szkle) z jasnym obrazem widocznym nawet w pełnym świetle dziennym. Pierwsze transparentne prototypy microLED już pokazano na CES 2024​.

QD-OLED

Technologia QD-OLED (Quantum Dot OLED) to hybryda łącząca zalety OLED i kropek kwantowych. Standardowe telewizory OLED (wielkoformatowe, jak LG) używają białych emiterów OLED + filtrów kolorów, zaś QD-OLED podchodzi do sprawy odwrotnie, wykorzystuje tylko niebieskie diody OLED jako źródło światła, a następnie część z nich zamienia na czerwone i zielone za pomocą warstw z kropek kwantowych​. Innymi słowy, każdy piksel składa się z subpikseli: niebieskiego (niezmienione emisje OLED) oraz czerwonego i zielonego, które powstają dzięki konwersji fotoluminescencyjnej. Niebieskie światło pobudza kropki kwantowe emitujące odpowiednio czystą czerwoną i zieloną barwę​. Takie rozwiązanie eliminuje tradycyjny filtr barwny, przez który w klasycznym OLED dużo światła się marnuje. QD-OLED świeci pełną mocą w wymaganych kolorach, co znacząco zwiększa jasność i nasycenie barw obrazu​. Zachowane są przy tym wszystkie atuty OLED-a. W praktyce QD-OLED osiąga efekty niemożliwe wcześniej dla OLED np. bardzo szeroką gamę kolorów przy wysokiej jasności.

Pierwsze telewizory z matrycami QD-OLED pojawiły się na rynku w 2022 roku. Technologię tę skomercjalizował jako pierwszy Samsung Display. QD-OLED to jedno z najciekawszych osiągnięć w dziedzinie wyświetlaczy ostatnich lat, już dostępne w sprzedaży. Produkty z tym ekranem jak telewizory Samsunga i Sony czy monitory Alienware pokazują przewagi tej technologii w praktyce, a trwające prace (większa jasność, większe rozmiary, potencjalnie niższy koszt w przyszłości) wskazują, że QD-OLED będzie zyskiwać na znaczeniu w segmencie wysokiej jakości ekranów.

Time for modern solutions

The history of display technology shows that progress in this field never stops. Do you want to work with specialists who understand this evolution and stay ahead of modern technology? At Device Prototype, our experts take care of every stage of electronics production, allowing you to focus on turning your ideas into reality. Contact us and see how we can support your project!