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Electronic visual display
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An electronic visual display is a display device that can display images, video, or text that is transmitted electronically. Electronic visual displays include television sets, computer monitors, and digital signage. They are ubiquitous in mobile computing applications like tablet computers, smartphones, and information appliances. Many electronic visual displays are informally referred to as screens, and those that also contain some means of touch input are called touchscreens.
Starting in the early 2000s, flat-panel displays began to dominate the industry, as cathode-ray tubes (CRT) were phased out, especially for computer applications. Starting in the mid 2010s, curved display panels began to be used in televisions, computer monitors, and smartphones.
Types
[edit]There are various technologies used for electronic visual displays:
- Liquid crystal display (LCD) including LED-backlit LCD
- LED display
- Plasma display
- Quantum dot display
- Electroluminescent display
An overhead projector can be considered a type of electronic visual display.[dubious – discuss]
Additionally, CRTs were widely used in the past and microLED displays are under development.
Classification
[edit]Electronic visual displays present visual information according to the electrical input signal (analog or digital) either by emitting light (then they are called active displays) or, alternatively, by modulating available light during the process of reflection or transmission (light modulators are called passive displays).[dubious – discuss]
| Electronic visual displays | ||
| Active displays | Passive displays | |
|---|---|---|
| present visual information by emitting light | present visual information by modulating light | |
| Principle | Liquid crystal display (LCD) + backlight (this combination is considered an active display) |
LCD |
| Example | LCD TV screen, LCD computer monitor | LCD watch (reflective) see LCD classification |
| Principle | Cathodoluminescence | Electrophoresis also see Electronic paper |
| Example | Cathode ray tube (CRT) Field emission display (FED) Vacuum fluorescent display (VFD) Surface-conduction electron-emitter display (SED) |
Research & manufacturing: |
| Principle | Electroluminescence | Electrochromism |
| Example | (thin or thick film) electro-luminescence (EL) (inorganic or organic) light emitting diode (LED, OLED) gas discharge display (Nixie tube) |
Research & manufacturing: |
| Principle | Photoluminescence | Electrowetting |
| Example | Plasma display panel (PDP) | Research & manufacturing: |
| Principle | Incandescence |
Electromechanical modulation |
| Example | Numitron, a 7-segment numerical display tube | flap display flip-disk display digital micromirror device (DMD) Interferometric modulator display (IMOD) FTIR (unipixel) |
Display mode of observation
[edit]Electronic visual displays can be observed directly (direct view display) or the displayed information can be projected to a screen (transmissive or reflective screen). This usually happens with smaller displays at a certain magnification.
| Display modes of observation | |
|---|---|
| Direct view display | Projection display |
| transmissive mode of operation | front-projection (with reflective screen) e.g. video projector |
| reflective mode of operation | rear-projection (with transmissive screen) e.g. rear projection television screen |
| transflective mode of operation (e.g. transflective LCD) |
retinal projection (with or without combiner) e.g. head mounted display |
A different kind of projection display is the class of "laser projection displays", where the image is built up sequentially either via line by line scanning or by writing one complete column at a time. For that purpose one beam is formed from three lasers operating at the primary colors, and this beam is scanned electro-mechanically (galvanometer scanner, micro-mirror array)) or electro-acousto-optically.
Layout of picture elements
[edit]Depending on the shape and on the arrangement of the picture elements of a display, either fixed information can be displayed (symbols, signs), simple numerals (7-segment layout) or arbitrary shapes can be formed (dot-matrix displays).
| Layout of picture elements | |
|---|---|
| Segmented displays characters, numbers and symbols of fixed shape (may be multiplex addressed) The following layouts are well known: Seven-segment display Fourteen-segment display Sixteen-segment display |
Dot-matrix displays sub-pixels are arranged in a regular 2-dimensional array (multiplex addressing required); arbitrary shapes can be formed and displayed |
Emission and control of colors
[edit]Colors can be generated by selective emission, by selective absorption, transmission or by selective reflection.
| Color emission and control | |
|---|---|
| additive mixing primary colors add up to produce white light |
subtractive mixing filters, dyes, pigments (e.g.printing) subtract (absorb) parts of white light |
| temporal mixing (additive) e.g. rotating primary color filter wheel in projectors |
spatial mixing (additive) closely spaced sub-pixels |
| spatio temporal color mixing combined spatial and temporal mixing[1] | |
| arrangement of sub-pixels for additive color mixing see sub-pixel arrangements 1 see sub-pixel arrangements 2 see sub-pixel arrangements 3 |
subtractive color mixing does not require special sub-pixel arrangements all components (e.g. filters) have to be in the same path of light. |
| Examples: stripe delta-nabla PenTile arrangement, e.g. RGB+White |
|
Addressing modes
[edit]Each sub-pixel of a display device must be selected (addressed) in order to be energized in a controlled way.
| Addressing modes (selection of picture elements) | |
|---|---|
| direct addressing each individual picture element has electrical connections to the driving electronics. |
multiplexed addressing several picture elements have common electrical connections to the driving electronics, e. g.. row and column electrodes when the picture elements are arranged in a two dimensional matrix. |
| active matrix addressing active electronic elements added in order to improve selection of picture elements.
|
passive matrix addressing the nonlinearity of the display effect (e.g. LCD, LED)is used to realize the addressing of individual pixels in multiplex addressing. In this mode only a quite limited number of lines can be addressed. In the case of (STN-)LCDs this maximum is at ~240, but at the expense of a considerable reduction of contrast. |
| The matrix of active electronic elements can be used in transmissive mode of operation (high transmittance required) or a non-transparent active matrix can be used for reflective LCDs (e.g. liquid crystal on silicon (LCOS)).| | |
Display driving modes
[edit]| Driving modes (activation of picture elements) | |
|---|---|
| voltage driving activation of pixels by voltage (e.g. LCD field effects). If the current is low enough this mode may be the basis for displays with very low power requirements (e.g. μW for LCDs without backlight). |
current driving activation of pixels by electric current (e.g. LED). |
See also
[edit]References
[edit]- ^ Louis D. Silverstein, et al., Hybrid spatial-temporal color synthesis and its applications, JSID 14/1(2006), pp. 3–13
- SID - Society for Information Display International Conference Proceedings 1970–2008
- Journal of the Society for Information Display (JSID)
- Display Reparatur (in German)
- Passive Displays
- Choosing an IT device Archived 2021-08-12 at the Wayback Machine
Further reading
[edit]- Pochi Yeh, Claire Gu: "Optics of Liquid Crystal Displays", John Wiley & Sons 1999, 4.5. Conoscopy, pp. 139
Electronic visual display
View on Grokipediafrom Grokipedia
| Type | Description | Key Characteristics | Common Applications |
|---|---|---|---|
| CRT | Electron beam scans a phosphor-coated screen to produce light. | High resolution (up to 2000 lines), Lambertian emission, gamma ~2.2; prone to flicker and aging.[1] | Legacy televisions and monitors (largely phased out by 2010s). |
| LCD | Liquid crystals twist to modulate backlight from LEDs or fluorescents. | Flat-panel, no flicker, luminance up to 700 cd/m²; viewing angle limitations in older models.[1] | Laptops, TVs, smartphones; active-matrix (AMLCD) variants for high-resolution needs. |
| Plasma | Gas cells ionized by electric fields to emit UV light, exciting phosphors. | Excellent contrast and color; high power use, risk of burn-in.[7] | Large-screen TVs (discontinued by mid-2010s). |
| OLED | Organic compounds emit light when voltage is applied; self-emissive. | Infinite contrast, flexible forms, wide viewing angles; potential degradation over time.[4] | High-end TVs, smartphones, wearables. |
| LED/MicroLED | Inorganic semiconductors emit light; microLED uses tiny chips for pixel-level control. | Bright (up to 10,000 cd/m² for backlights), long lifespan; scalable for large displays.[3] | Digital signage, outdoor billboards, emerging modular TVs. |
Overview
Definition and Principles
An electronic visual display is a device that converts electrical signals into visible images by controlling the emission, modulation, or reflection of light, serving as a critical interface for presenting information in applications such as computer monitors, television screens, and digital signage.[11] The fundamental principles of electronic visual displays rely on mechanisms that manipulate light at the pixel level to form images. These include electron excitation, where electrons are energized to produce light emission; photoluminescence, involving the absorption and re-emission of photons by materials; liquid crystal alignment, which modulates light transmission through oriented molecules; and plasma ionization, where gas is excited to generate luminous plasma. These processes enable the creation of dynamic visual content by selectively activating or altering light properties across the display surface.[11] Key performance indicators for electronic visual displays include luminance, measured in candelas per square meter (cd/m²) to quantify brightness; contrast ratio, the ratio of the luminance of the brightest white to the darkest black; refresh rate, expressed in hertz (Hz) as the frequency of image updates; and response time, in milliseconds (ms), indicating the speed of pixel state transitions. These metrics determine the display's suitability for various uses, such as static viewing or high-motion content.[11] The control of electronic visual displays has evolved from analog signals, which transmitted continuous waveforms like those in VGA or NTSC standards, to digital signals using discrete data streams in formats such as HDMI and SDI, enabling higher resolution, reduced noise, and integrated audio-video transmission since the 1990s.[12]Historical Evolution
The development of electronic visual displays began in the late 19th century with the invention of the cathode ray tube (CRT) by German physicist Karl Ferdinand Braun in 1897, which served as the foundational technology for visual signal representation.[13] Braun's CRT, often called the Braun tube, used an electron beam to project images onto a fluorescent screen, enabling the first cathode-ray oscilloscope for visualizing electrical waveforms.[14] This device marked a pivotal shift from mechanical to electronic methods of display, laying the groundwork for subsequent applications in scientific instrumentation. During the mid-20th century, CRT technology proliferated in consumer and military uses, particularly from the 1920s to the 1950s, as it became integral to early televisions and radar systems.[15] The first practical television transmissions using CRTs emerged in the 1920s, with Vladimir Zworykin patenting the kinescope in 1929, which facilitated the commercial rollout of black-and-white TVs by the 1940s and color sets by the 1950s.[16] In parallel, CRTs were essential for radar displays during World War II, where they visualized radio wave echoes on screens to detect aircraft and ships, significantly enhancing Allied defensive capabilities.[17] By the 1950s, CRT-based televisions had become household staples, dominating the market due to their reliable image reproduction. The 1960s and 1970s introduced alternative technologies that challenged CRT dominance, starting with the first plasma display prototype in 1964, developed by Donald Bitzer and Gene Slottow at the University of Illinois for computer terminals.[18] This monochrome plasma panel offered flat, flicker-free visuals, though initial applications were limited to niche educational systems like PLATO.[19] Concurrently, liquid crystal displays (LCDs) advanced with George H. Heilmeier's demonstration of the first dynamic scattering LCD at RCA in 1968, patented as a light-modulating device for low-power applications.[20] Early LCDs appeared in calculators and watches by the 1970s, providing thinner profiles than CRTs. From the 1980s to the 1990s, plasma and LCD technologies matured alongside CRTs, with plasma gaining traction in professional monitors—IBM released the first commercial plasma display in 1973—and LCDs expanding into portable devices amid the integration of digital signal processing for improved image handling. The 1980s also saw the adoption of digital circuits in CRT televisions, enhancing signal processing for better picture quality and paving the way for high-definition standards.[21] However, CRTs remained prevalent until the early 2000s, when flat-panel displays overtook them due to superior thinness, lighter weight, and lower power consumption; by 2005, LCD production volumes surpassed CRTs globally.[22] Entering the 2010s, the industry transitioned fully to flat-panels, with CRT production ceasing in major markets by 2010—the last U.S. rebuilder closed that year—and Europe following in 2013. Sony introduced the first commercial OLED television in 2007, with Samsung commercializing OLED panels for televisions starting in the early 2010s, enabling self-emissive displays with superior contrast and flexibility, which rapidly displaced LCDs in premium segments.[23] Mid-decade innovations like curved displays emerged in 2013, led by Samsung and LG, aiming to enhance immersion in large TVs through panoramic viewing angles, though they peaked briefly before flat designs reclaimed dominance.[24] This era solidified flat-panel technologies as the standard, driven by manufacturing scalability and consumer demand for sleeker, energy-efficient screens.Types
Traditional Technologies
The cathode-ray tube (CRT) represents one of the earliest and most foundational electronic visual display technologies, dominating consumer and professional applications for much of the 20th century. In a CRT, an electron gun at the rear of the vacuum tube generates a beam of electrons, which is accelerated toward a phosphor-coated screen at the front. Magnetic deflection coils or electrostatic plates precisely steer and focus the beam to scan across the screen in a raster pattern, where it strikes the phosphors to produce visible light through cathodoluminescence; red, green, and blue phosphors are arranged in a shadow mask or aperture grille structure to enable color reproduction.[25][26] CRTs offered notable advantages in display performance, including superior color accuracy due to the direct excitation of phosphors, which provided wide color gamuts and high fidelity without the need for backlighting, as well as excellent motion handling from fast phosphor decay times and high refresh rates, minimizing blur in dynamic content like video games or broadcast television.[25] However, these benefits came at significant costs: CRTs were inherently bulky and heavy due to the large vacuum envelope required to maintain electron beam paths, consumed substantial power—often hundreds of watts for larger screens—and emitted low levels of X-ray radiation, necessitating leaded glass shielding that raised health and safety concerns.[25] Plasma display panels (PDPs), developed in the late 1960s but commercialized prominently in the 1990s, emerged as a flat alternative to CRTs for large-screen applications, particularly high-definition televisions in the 2000s. Each PDP consists of thousands of tiny gas-filled cells sandwiched between glass panels; when a high voltage is applied across electrodes, the inert gas mixture (typically neon and xenon) ionizes to form plasma, emitting ultraviolet (UV) photons that excite red, green, or blue phosphors coating the cell walls to produce visible light.[27] This self-emissive process allowed for deep blacks and high contrast ratios, often exceeding 1000:1, making PDPs particularly effective for cinematic viewing in ambient light conditions.[27] Despite these strengths, PDPs suffered from drawbacks that limited their longevity, including high power consumption—typically 200-400 watts for 42-50 inch models due to the energy-intensive gas discharge process—and susceptibility to burn-in, where prolonged display of static images caused permanent phosphor degradation and uneven luminance.[27][28][29] CRTs held over 80% of the global television unit market share through much of the early 2000s, with shipments peaking at around 130 million units in 2005 before rapidly declining as flat-panel alternatives gained traction.[30] PDPs, meanwhile, peaked in popularity during the mid-2000s for HDTVs over 40 inches, capturing significant share in premium large-screen segments before production ceased by 2014 due to intensifying competition from more efficient liquid-crystal displays (LCDs).[31] The transition away from these traditional technologies was driven by their bulkiness, energy inefficiency, and environmental impacts, such as the lead content in CRT funnel glass, which classifies discarded units as hazardous waste capable of leaching toxins into soil and water if not properly managed.[32][33]Flat-Panel Technologies
Flat-panel technologies have revolutionized electronic visual displays by enabling thin, energy-efficient panels that dominate consumer electronics. Liquid crystal displays (LCDs) and organic light-emitting diode (OLED) displays are the primary types, with LCDs leveraging liquid crystals to modulate backlight for image formation and OLEDs using self-emissive organic materials for direct light generation. These technologies prioritize scalability, cost, and performance trade-offs, such as viewing angles, contrast, and power use, making them suitable for televisions, monitors, and portable devices. Liquid crystal displays consist of a layer of liquid crystals between two glass substrates, where the crystals' orientation controls light transmission from a rear backlight. In twisted nematic (TN) mode, the liquid crystals form a helical structure that rotates polarized light by 90 degrees when unpowered, allowing light to pass; applying voltage untwists the helix to block light.[34] In-plane switching (IPS) mode aligns crystals horizontally, enabling better color consistency and wider viewing angles by minimizing light leakage at off-angles.[35] Pixel control is provided by thin-film transistor (TFT) arrays on the substrate, which apply voltages to switch individual liquid crystal cells.[35] LCD backlighting evolved from cold cathode fluorescent lamps (CCFL) to LEDs for higher efficiency and reduced thickness, with CCFL phased out by the mid-2000s in favor of LED sources that offer longer life and lower power draw. LED configurations include edge-lit, where LEDs line the panel edges to illuminate a light guide plate, providing slim designs but limited contrast control, and full-array local dimming, which places LED zones directly behind the panel to independently dim areas for deeper blacks and higher dynamic range.[36] LCD variants address specific trade-offs: TN panels deliver fast response times ideal for gaming but suffer narrow viewing angles; vertical alignment (VA) improves contrast by aligning crystals perpendicularly for better light blocking; and IPS excels in wide viewing angles up to 178 degrees with accurate colors, though at the cost of slightly slower response.[37] Organic light-emitting diode displays feature thin organic layers between electrodes that emit light upon current flow, with each pixel independently controllable for true per-pixel lighting. Structures include RGB OLEDs, where red, green, and blue subpixels use distinct organic emitters, or white OLEDs paired with color filters to produce full color while simplifying fabrication.[38] This self-emissive nature yields infinite contrast ratios with perfect blacks and enables flexible, lightweight panels on plastic substrates.[39] LCDs have commanded over 90% market share in large-area flat-panel displays, particularly televisions, throughout the early 2020s, driven by mature manufacturing and affordability.[40] OLEDs gained traction in premium televisions starting in the 2010s, with commercial large-screen models introduced around 2013.[41] Quantum dot enhancements in LCD backlights improve efficiency by converting blue LED light to narrow-band red and green, boosting color gamut coverage and brightness by up to 30% at 30-50% lower power than standard LCDs.[42] Key limitations include backlight bleed in LCDs, where uneven illumination causes glow in dark areas due to light diffusion from the always-on backlight, and burn-in in OLEDs, resulting from uneven organic material degradation under prolonged static images.[43][44]Emerging Technologies
MicroLED displays consist of inorganic LED arrays that enable pixel-level self-emission, providing exceptionally high brightness exceeding 10^7 nits and resistance to burn-in, unlike organic LED technologies.[45] These displays leverage microscale red, green, and blue LEDs for superior efficiency and longevity, though manufacturing challenges, including low yields from mass transfer processes, have hindered widespread adoption.[46] Prototypes emerged in the early 2020s, such as Samsung's 2021 demonstration of a 75-inch TV, marking initial progress toward high-resolution applications.[47] By 2025, commercial implementations have advanced in wearables and automotive sectors, with innovations like VueReal's MicroSolid Printing enabling transparent and flexible integrations.[48] Market analyses project MicroLED to dominate the premium display segment, surpassing OLED revenues by the mid-2030s due to its scalability in large-format and AR/VR uses.[49] Quantum dot displays employ layers of semiconductor nanocrystals to boost color accuracy and luminous efficiency in backlit LCDs and OLEDs, expanding the color gamut to cover up to 100% of the DCI-P3 standard for vivid reproduction.[50] Branded as QLED in Samsung's lineup, this technology functions as an enhanced LCD variant, where quantum dots convert blue LED light into pure red and green emissions, reducing energy loss.[50] By 2025, quantum dots have been integrated into a significant portion of premium televisions from manufacturers like Samsung, TCL, Sony, and Hisense, earning certifications for authentic performance and driving market growth to over USD 25 billion globally.[51][52] Flexible and foldable displays, primarily based on OLED substrates, allow screens to bend, roll, or stretch without compromising image quality, enabling compact form factors for portable devices.[53] Early prototypes, such as LG's 2019 rollable OLED TV, demonstrated seamless expansion from 65 to 88 inches, while Samsung's Galaxy Fold series, launched in 2019, popularized foldable smartphones with durable hinge mechanisms.[54] Advancements by 2025 include Samsung's stretchable microLED concepts at Mobile World Congress, capable of 10-20% elongation, and LG's 12-inch stretchable panels expanding up to 50% for wearable and automotive applications.[53][55] Rollable OLED laptops from Lenovo and Samsung entered production in 2025, projecting market expansion to USD 35 billion by 2030 through innovations in ultra-thin substrates and encapsulation.[54][56] Other emerging technologies include electrowetting displays, which use electric fields to manipulate colored oil droplets for fast-switching, reflective visuals with video-rate refresh, though limited by scalability and entering niche markets like smartwatches by 2025.[57] Electrophoretic displays, exemplified by E Ink's e-paper, rely on charged particles in microcapsules for bistable, low-power operation ideal for e-readers and signage, with 2025 breakthroughs in color-rich, large-format panels operating from -20°C to 65°C.[58][59] Holographic projection displays advance through metasurface integrations with OLEDs, enabling compact, real-time 3D imaging without glasses for AR and automotive HUDs, as demonstrated in 2025 prototypes achieving sub-300nm pixel pitches.[60][61]Classification
By Light Emission and Modulation
Electronic visual displays are fundamentally classified by their mechanisms of light emission and modulation, which determine how images are formed through the control of light sources or ambient illumination. This distinction separates emissive displays, which generate their own light, from non-emissive types that rely on external or backlit light sources modulated by material properties. Such classification highlights trade-offs in power consumption, contrast, and visibility under varying lighting conditions.[62] Emissive displays produce light directly at the pixel level, enabling high brightness and wide viewing angles without requiring a separate backlight. In these devices, electrical energy excites luminescent materials to emit photons, as seen in cathode ray tubes (CRTs), where electron beams strike phosphors on a screen to generate visible light through electron transitions. Organic light-emitting diode (OLED) displays represent a modern emissive technology, where electrons and holes recombine in organic layers to produce light emission, offering flexibility and thin profiles suitable for curved or wearable applications. Subtypes include electroluminescent (EL) displays, which use an alternating electric field to excite phosphors for light emission, and field emission displays (FEDs), which employ cold cathode arrays to emit electrons that excite phosphors, mimicking CRT principles in a flat-panel format. These emissive technologies achieve superior contrast ratios, including infinite blacks, by completely deactivating pixels to emit no light, enhancing image depth in dark environments.[62][29][63][64][65] Transmissive or modulative displays, such as liquid crystal displays (LCDs), do not generate light but instead control its passage through the panel using polarizing filters and liquid crystal molecules. In LCDs, liquid crystals align under an electric field to twist or modulate polarized light from a backlight, allowing selective transmission to form images; this requires two polarizers to block or pass light based on molecular orientation. These displays dominate consumer markets due to their lower manufacturing costs compared to emissive alternatives like OLEDs, enabling scalable production for televisions and monitors. However, they exhibit limited contrast because black levels depend on backlight leakage through imperfect modulation.[63][62][66] Reflective displays utilize ambient light reflected off the panel surface, consuming minimal power by avoiding internal illumination, which makes them ideal for battery-powered devices like e-readers. Electrophoretic displays, such as those in E Ink technology, operate via electrophoresis, where charged pigment particles in microcapsules migrate under an electric field to create visible contrasts by absorbing or reflecting external light. This bistable nature allows static images to persist without power, achieving paper-like readability and low energy use in outdoor or mobile settings.[67][62] Hybrid approaches combine modulation with emissive enhancements for improved efficiency, as in quantum dot (QD)-enhanced LCDs, where nanoscale semiconductor particles convert backlight wavelengths to achieve wider color gamuts and higher brightness with less energy loss. These systems integrate QDs as color filters or down-converters, bridging the gap between transmissive cost-effectiveness and emissive performance.[68]By Addressing and Driving
Electronic visual displays are classified by addressing and driving methods based on how electrical signals control pixel activation and intensity. Addressing refers to the selection of pixels for update, while driving pertains to the signal application for emission or modulation. These methods determine resolution, power efficiency, and suitability for applications ranging from low-resolution indicators to high-definition screens.[69] Matrix addressing is the predominant technique in modern displays, organizing pixels in a grid where rows and columns are scanned sequentially to select and energize elements. In passive matrix addressing, pixels form at row-column intersections without individual switching elements, relying on simple diode or resistor networks for control, which limits resolution due to crosstalk and voltage drop in larger arrays. This approach suits low-resolution displays, such as early alphanumeric LCDs, achieving contrast ratios around 15:1.[70][71][72] Active matrix addressing enhances performance by incorporating a thin-film transistor (TFT) or similar switch at each pixel, enabling precise control and storage of charge to maintain state during scanning. This method supports high resolutions and fast refresh rates, becoming the standard for over 90% of flat-panel displays since the 1990s, including most LCDs and AMOLEDs. Row-column scanning remains central, but the TFT isolates pixels, reducing crosstalk and allowing grayscale via voltage holding.[69][73] Direct addressing provides individual control to each pixel or segment without a matrix, typically used in small-scale displays like compact OLED indicators or seven-segment digits. Here, dedicated lines connect directly to elements, avoiding scanning delays and enabling simpler circuitry for low-pixel-count applications, such as wearable device sub-displays.[74] Driving methods further classify displays by signal type for intensity control. Analog driving applies variable voltage or current to pixels, directly modulating light output for smooth grayscale reproduction in technologies like LCDs. Digital driving, conversely, uses binary signals with techniques such as pulse-width modulation (PWM), where duty cycle varies on-time to simulate analog levels, common in OLEDs for efficient dimming without color shifts. PWM offers wide dynamic range and reduced power in low-brightness scenarios compared to analog methods.[75][76][77] Emerging approaches include scanless addressing in microLED displays, where block-based or parallel control activates groups of pixels simultaneously via FPGA-driven systems, bypassing traditional row scanning for higher throughput in high-density arrays. Additionally, as of 2025, AI-optimized driving integrates predictive algorithms into controllers to dynamically adjust signals for power savings, as demonstrated in collaborations like Intel and BOE's technology, which fine-tunes consumption in real-time while preserving image quality.[78][79][80]By Application and Form Factor
Electronic visual displays are classified by their applications in consumer, industrial, and professional contexts, as well as by their physical form factors, which determine suitability for specific use cases and environments. In consumer applications, large-screen televisions dominate home entertainment, often featuring sizes exceeding 55 inches with support for 4K and higher resolutions using LED-backlit LCD or OLED panels to deliver immersive viewing experiences.[81] Desktop computer monitors typically employ rigid flat LCD or OLED technologies for productivity and gaming, with curved variants introduced in the 2010s to enhance peripheral vision and reduce eye strain during extended use.[2] Mobile devices, such as smartphones, commonly utilize AMOLED displays for their vibrant colors, high contrast ratios, and energy efficiency in compact form factors.[82] Industrial and professional applications demand displays optimized for durability, precision, and specialized functionality. Medical imaging relies on high-resolution LCD panels calibrated for accurate color reproduction and grayscale rendering to support diagnostics, often meeting standards like DICOM for consistent visualization of patient data.[83] In automotive settings, head-up displays (HUDs) project critical information onto the windshield using transparent OLED or LCD optics, allowing drivers to maintain focus on the road while accessing navigation and speed data.[84] Digital signage employs high-brightness LED displays capable of outdoor visibility exceeding 5,000 nits, enabling dynamic content delivery in retail and public spaces for advertising and information dissemination.[85] Form factors further differentiate displays by physical configuration and adaptability. Rigid flat panels remain the standard for most stationary applications due to their structural stability and cost-effectiveness in manufacturing. Flexible and curved displays, exemplified by Samsung's curved OLED televisions launched in the mid-2010s, offer panoramic viewing angles and aesthetic integration into home setups. Wearable and near-eye displays, such as micro-OLED panels in virtual reality (VR) headsets, provide high pixel densities over 3,000 ppi in compact, lightweight forms for immersive extended reality experiences. Augmented reality (AR) and VR displays are projected to grow at 39.2% in shipments during 2025, driven by advancements in optics and content ecosystems. The automotive sector is shifting toward OLED-based dashboards, with annual shipment growth nearing 40% through 2030, enabling seamless, high-contrast interfaces across vehicle interiors. E-ink displays, known for their low power consumption and sunlight readability, are increasingly adopted in retail for electronic shelf labels and pricing signage, reducing paper waste and enabling remote updates. Post-2019 developments in foldable smartphones, led by Samsung's Galaxy Fold series, have popularized flexible OLED screens that unfold into tablet-like formats for enhanced multitasking. Transparent displays, often using OLED or LED technologies, are gaining traction in retail for applications like interactive window showcases and virtual try-on mirrors, blending digital content with physical environments without obstructing views.[86][87][88][89][90][91][92]Display Characteristics
Picture Element Layout
In electronic visual displays, the picture element, or pixel, serves as the fundamental unit of image formation. For monochrome displays, a single pixel element suffices to represent varying intensities of a single color, typically black to white or green in early systems.[93] In color displays, which dominate modern applications, each pixel consists of a triplet of subpixels—red, green, and blue (RGB)—arranged to produce a full spectrum of colors through additive mixing.[94] This subpixel structure enables higher effective resolution while managing manufacturing complexity, as the human eye perceives the combined output as a single colored dot. Pixel layouts vary to optimize resolution, color fidelity, and cost. The RGB stripe arrangement aligns subpixels horizontally or vertically in a linear fashion, common in many LCDs for straightforward addressing and uniform sharpness across the image.[95] In contrast, the delta layout positions RGB subpixels in a triangular pattern, enhancing color blending and reducing moiré patterns in certain viewing angles, though it complicates driver electronics.[96] Mosaic patterns, often seen in advanced LCDs, employ irregular or hexagonal subpixel grids to improve light efficiency and angular viewing, distributing color elements more evenly than strict stripes.[97] For AMOLED displays, the PenTile matrix uses an RGBG scheme with fewer total subpixels—twice as many green elements as red or blue—to cut production costs and yield, while relying on subpixel rendering algorithms to approximate full RGB density.[98] Resolution defines the total addressable pixels, directly impacting image detail and sharpness. Common standards range from VGA at 640 × 480 pixels, suitable for basic computing, to 8K ultra-high definition at 7680 × 4320 pixels, enabling immersive experiences in large-scale viewing.[99][100] The total pixel count is calculated as , where is the horizontal pixel dimension and is the vertical; for instance, a 4K display yields pixels.[101] Pixel density, measured in pixels per inch (PPI), quantifies sharpness on a given screen size. To derive PPI, first compute the diagonal resolution in pixels using the Pythagorean theorem: . Then, divide by the physical diagonal screen size in inches: , where is the diagonal length; higher PPI values, such as over 300 in smartphones, minimize visible pixelation.[102] Aspect ratios shape the pixel grid's proportions, influencing content framing. Early standards like 4:3 suited square-like formats for text and video, while modern widescreen ratios progress to 16:9 for cinema and broadcasting, and ultrawide 21:9 for immersive multitasking on monitors.[103] These ratios dictate pixel dimensions—for example, a 1920 × 1080 display maintains 16:9—requiring content adaptation to avoid distortion. In high-resolution setups, anti-aliasing techniques become essential to smooth jagged edges (aliasing) from diagonal lines, as denser pixels amplify subpixel visibility despite reducing overall need compared to lower resolutions.[104]| Resolution Standard | Dimensions (pixels) | Aspect Ratio | Typical Use Case |
|---|---|---|---|
| VGA | 640 × 480 | 4:3 | Legacy computing |
| Full HD | 1920 × 1080 | 16:9 | HDTV broadcasting |
| 4K UHD | 3840 × 2160 | 16:9 | Professional video |
| 8K UHD | 7680 × 4320 | 16:9 | Future-proof large screens |
| Ultrawide 3440 | 3440 × 1440 | 21:9 | Gaming and productivity |