Reference appendices | LED Perfection

Appendix A. Timeline: more than a century of LED innovation

1907 - Electroluminescence recorded

Henry Joseph Round publishes a short account of light emission from silicon carbide while working on crystal detectors. The event is generally treated as the first recorded observation leading to the LED.

1920s - Losev investigates light-emitting crystals

Oleg Losev publishes experimental work on electroluminescence and considers signalling applications. His contribution is later recognised as foundational to LED history.

1947 - The transistor begins the semiconductor era

John Bardeen, Walter Brattain and William Shockley demonstrate the transistor at Bell Laboratories. The resulting growth in semiconductor physics and manufacturing creates essential knowledge for LEDs and integrated electronics.

1950s - Compound-semiconductor research accelerates

Researchers investigate gallium arsenide, gallium phosphide and related materials for infrared and visible emission. Junction growth, doping and contact techniques improve.

1962 - The practical visible red LED

Nick Holonyak Jr and colleagues at General Electric demonstrate a practical red gallium-arsenide-phosphide LED. The University of Illinois records a successful visible demonstration on 9 October 1962.

Late 1960s - Commercial indicators expand

LEDs appear in instruments, industrial equipment and consumer products. Their long life and low power make them attractive replacements for miniature lamps in indicator roles.

1968 - Daktronics is founded

Daktronics begins in Brookings, South Dakota, and develops scoring and timing products before expanding into large video and venue systems.

Early 1970s - Numeric displays enter mass use

Seven-segment LED displays become familiar in calculators, clocks and test equipment. Matrix-addressing and driver techniques develop alongside the semiconductor devices.

1980 - Diamond Vision at Dodger Stadium

Mitsubishi Electric's corporate history records a Diamond Vision installation at Dodger Stadium, an important commercial milestone for giant full-colour public video.

1985 - Sony JumboTron at Expo '85

Sony presents JumboTron at the International Exposition in Tsukuba. The early system uses Trinilite elements rather than modern direct-view LED, but helps establish the cultural expectation of giant live video.

Late 1980s to early 1990s - Gallium nitride breakthroughs

Isamu Akasaki and Hiroshi Amano develop high-quality gallium nitride structures and p-type material. Shuji Nakamura advances practical high-brightness blue devices. Together, the work enables efficient blue light emission.

Mid-1990s - Full-colour outdoor LED grows

Commercial RGB screens begin to spread through stadiums, public events and city-centre advertising. Large pixel pitches are acceptable because viewers are far from the display.

Late 1990s - Broadcast and rental performance improves

Higher refresh, better colour, lighter cabinets and digital processing expand LED use in touring, broadcast and staged events. Lighthouse Technologies is among the companies active in this period.

1999 - Macroblock is founded

The Taiwan-based company specialises in LED driver integrated circuits, illustrating the growing importance of dedicated driver technology to display quality and efficiency.

Early 2000s - Shenzhen becomes the production centre

Dense electronics supply chains in Shenzhen and the Pearl River Delta support rapid growth in modules, cabinets, processors and complete displays. Global pricing falls and product development accelerates.

2001 - Absen is established

Absen develops from Shenzhen into an international LED display manufacturer serving rental and fixed-installation markets.

2004 - Unilumin is established

Unilumin becomes part of the expanding Chinese display industry and later develops broad commercial and professional product ranges.

Mid-2000s - SMD supports smaller pitches

Compact RGB surface-mount packages, improved placement and better driver electronics enable more practical indoor products and wider viewing angles.

Late 2000s - Fine-pitch indoor LED emerges

LED begins to challenge projection and tiled LCD in control rooms, broadcast and premium commercial spaces. The market increasingly evaluates black level, low greys and close viewing.

2011 - Brompton Technology is founded

The UK company focuses on LED video processing and later becomes strongly associated with high-end live events and virtual production.

2014 - Blue-LED researchers receive the Nobel Prize

Isamu Akasaki, Hiroshi Amano and Shuji Nakamura receive the Nobel Prize in Physics for efficient blue light-emitting diodes, recognising a breakthrough that enabled bright, energy-efficient white light and full-colour LED systems.

2016 - ITU-R BT.2100 formalises HDR television systems

The ITU publishes a recommendation covering high-dynamic-range television with perceptual quantiser and hybrid log-gamma approaches. Display workflows increasingly address peak luminance, black level and tone reproduction as a system.

Late 2010s - Integrated packaging expands

COB, IMD, GOB and related approaches attract attention as manufacturers pursue finer pitch, stronger surfaces and better ambient contrast.

2019-2021 - LED virtual production enters mainstream awareness

High-profile film and television productions demonstrate large LED volumes with camera tracking and real-time rendering. Studios and broadcasters begin investing in permanent and temporary stages.

Early 2020s - Fine pitch moves below 1 mm

Sub-millimetre products become commercially available for premium close-viewed applications, although cost, viewing conditions and supportability remain central to suitability.

2023 - New MicroLED assembly research

Peer-reviewed work demonstrates fluidic and other self-assembly approaches for transferring very small LEDs, addressing one of the major barriers to scalable MicroLED manufacture.

2025 - MicroLED research focuses on manufacturability

Academic reviews describe progress in emitters, transfer, colour conversion, testing and integration while continuing to identify yield and cost as major challenges.

2026 - Wider access to media standards

SMPTE opens its standards library for free access, supporting wider participation in professional media interoperability and timing.

The continuing timeline

The next milestone may be a manufacturing method, a packaging architecture, an energy breakthrough, an open control standard or a new creative use. The recurring pattern is that display progress depends on several disciplines advancing together.

Appendix B. A-Z glossary of LED video display terms

A

Active area: The part of a display surface that emits the intended image. Mechanical borders and inactive gaps are excluded.

Ambient light: Light already present in the viewing environment. It can reduce perceived contrast through reflections and affect the required operating luminance.

Aspect ratio: The proportional relationship between image width and height, such as 16:9.

Average picture level (APL): A measure of the overall brightness of an image. High-APL content such as a white document can draw more power and appear brighter than a dark scene.

B

Binning: Sorting LEDs or components into groups with similar optical or electrical characteristics. Binning helps consistency but does not remove all variation.

Bit depth: The number of digital code values available for a colour channel. Higher bit depth can support smoother gradients when the complete signal chain preserves it.

Black level: The luminance or visual appearance of the display when it is intended to show black. Ambient reflections can dominate black level in bright rooms.

Brightness: A general visual term. For displays, the measured quantity is usually luminance in candelas per square metre.

C

Cabinet: A mechanical and electronic building block containing modules, receiving electronics and power distribution. Some manufacturers use terms such as panel or tile.

Calibration: Measurement and correction of luminance or colour variation against a target. The method and correction storage are product-specific.

Candela per square metre (cd/m2): The SI-derived unit used for display luminance. One cd/m2 is commonly called one nit.

Chip-on-board (COB): An architecture in which bare LED dies are mounted to a substrate and encapsulated as an integrated surface.

Colour gamut: The range of colours a system can reproduce within a defined colour space.

Colour space: A formal system for describing colour values, primaries, white point and other image characteristics. Examples include systems based on BT.709 and BT.2020.

Colour temperature: A way of describing the appearance of white in kelvin. A menu value should be verified by measurement if accuracy matters.

Content management system (CMS): Software used to upload, schedule, approve and distribute content to digital displays.

Contrast ratio: A ratio between a bright and dark measurement. The result depends strongly on test method and ambient light.

Controller: Hardware or software that converts and distributes image data to the LED display. Terminology varies by manufacturer.

D

Dead pixel: A pixel or subpixel that does not emit as intended. The visible symptom does not identify the root cause by itself.

Digital out-of-home (DOOH): Digital advertising and information media located in public or commercial spaces outside the home.

DIP: Dual in-line package, commonly used in the LED industry for discrete through-hole LED packages.

Direct-view LED: A self-emissive display in which LEDs at the viewing surface form the image, rather than illuminating an LCD or a projection screen.

Driver IC: An integrated circuit that controls current, timing and scanning for groups of LEDs.

Duty cycle: The proportion of time for which a device or signal is active. In PWM, it influences perceived light output.

E

Electroluminescence: Light emission produced by electrical excitation of a material. It is the physical phenomenon underlying LEDs.

EMC: Electromagnetic compatibility: the ability of equipment to operate as intended without causing or suffering unacceptable electromagnetic disturbance.

Encapsulation: Protective optical material surrounding LED dies or packages. It influences durability, reflection and light distribution.

End of life: The point at which an asset no longer meets acceptable safety, performance, supportability or economic criteria. It is not necessarily a single hour threshold.

F

Failover: A controlled change to a backup source, processor, controller, power path or other redundant element after a failure.

Fine pitch: An informal term for relatively small pixel pitch, commonly used for close-viewed indoor LED. The numerical boundary changes as the market develops.

Frame rate: The number of complete source images presented per second.

Front service: A product architecture allowing defined service access from the viewing side. The exact accessible assemblies and safe method vary.

G

Gamma: A term commonly used for the relationship between signal code values and displayed luminance in standard-dynamic-range systems.

Genlock: Synchronisation of video devices to a common timing reference.

Glue-on-board (GOB): A protective resin or coating applied over a populated LED module, often over SMD packages.

Greyscale: The ability to reproduce levels between black and white. In RGB displays, low-level greys also reveal colour balance and bit-depth behaviour.

H

HDR: High dynamic range. A system combining defined transfer functions, colour and luminance capabilities to represent a wider range between dark and bright detail.

Hot pixel: A pixel or subpixel that remains too bright or active when it should be dark.

I

Image processor: A device or software system that scales, switches, composites, maps or colour-converts content before display.

IMD: Integrated matrix device, generally a package containing several pixels. Implementation varies by supplier.

Ingress protection (IP) code: A classification under IEC 60529 for enclosure protection against access, solid objects and water.

Input latency: Delay introduced from receipt of a source signal to its visible output, often only one part of total system latency.

J

Jumbotron: Sony's historical giant-screen brand. The word is often used generically, but early JumboTron systems were not modern direct-view LED.

L

Latency: Time between an event or input and its visible result. The total can include capture, processing, network, render and display delays.

LED: Light-emitting diode, a semiconductor device that emits light when appropriately energised.

LED batch: A production grouping of LEDs or modules with shared manufacturing characteristics. Batch differences can affect colour and luminance matching.

LED television: Usually an LCD television using an LED backlight, not a direct-view LED display.

L70: A lifetime criterion meaning the time until light output falls to 70 per cent of an initial value under defined conditions. It is more common in lighting and should not be assumed to describe complete display life.

Luminance: Luminous intensity per projected area in a specified direction, commonly measured in cd/m2 for displays.

M

Mapping: Assigning parts of the source image to the physical pixel locations of the display.

Media facade: An architectural surface that incorporates digital light or display elements to present imagery or information.

Media server: A computer system designed to play, composite or render media, often across unusual canvases or multiple outputs.

MicroLED: A display approach using microscopic inorganic LED emitters. Exact size definitions vary.

MiniLED: A term used for small LEDs in either advanced LCD backlights or direct-view emissive displays. Architecture must be confirmed.

MIP: MicroLED-in-package, generally referring to small LED dies assembled into packages before placement on a display substrate.

Module: A circuit assembly containing a repeated matrix of LED pixels. Several modules normally form a cabinet.

Moiré: An interference pattern caused by interaction between repeating spatial structures, such as an LED pixel grid and a camera sensor.

N

Native resolution: The physical pixel dimensions of a display. Content at native resolution avoids an additional spatial scaling step.

Nit: A non-SI name commonly used for one candela per square metre.

O

OLED: Organic light-emitting diode. A different self-emissive display technology using organic materials.

Optical mask: A dark structure around or between LEDs used to control reflections, contrast and light distribution.

P

Panel: An ambiguous industry term that may mean a cabinet, module, complete display section or flat-panel product. Define it in project documents.

Pixel: The smallest independently addressed picture element, commonly formed from red, green and blue subpixels.

Pixel density: The number of pixels within a physical area. It rises as pixel pitch becomes smaller.

Pixel map: A document or file showing the exact arrangement and coordinates of the display's active pixels.

Pixel pitch: Centre-to-centre spacing between adjacent pixels, usually in millimetres.

Power factor: The relationship between real power and apparent power in an AC electrical system. It can influence distribution design.

Processor: See image processor. In some systems, processing and display control are combined.

PWM: Pulse-width modulation, a method of controlling perceived LED output by varying on-time within rapid cycles.

R

Rear service: A display requiring or permitting service access from behind the screen.

Receiving card: A common term for electronics within a cabinet that receive display data and distribute it to modules. Product architectures vary.

Redundancy: Duplication of selected system paths or components to reduce the consequence of a failure.

Refresh rate: The rate at which display information is updated or repeated. It is not the same as source frame rate.

Resolution: The number of addressable pixels horizontally and vertically.

RGB: Red, green and blue, the additive primary colours used in most full-colour LED displays.

S

Scan ratio: A description of multiplexed row driving, such as 1/8 or 1/16 scan. It influences timing, luminance and driver load.

SDR: Standard dynamic range, a family of conventional video systems with different transfer and luminance assumptions from HDR.

Seam: The physical boundary between modules or cabinets. Mechanical or optical variation can make it visible.

Sending device: A general term for the controller hardware that sends display-specific data to receiving electronics.

Service access: The physical route and working space required for authorised inspection, replacement or repair.

SMD: Surface-mount device. In LED displays, commonly a package containing red, green and blue dies mounted to the circuit board surface.

Subpixel: A red, green or blue light-emitting element contributing to one full-colour pixel.

T

Tile: Another ambiguous term for a module, cabinet or larger display unit. Project documentation should define its meaning.

Tone mapping: Conversion of image luminance from one dynamic range or display capability to another while preserving intended detail and appearance as far as possible.

Total cost of ownership: The combined cost of purchase, infrastructure, content, energy, support, downtime, access, refurbishment and end-of-life treatment.

Transfer function: A defined relationship between digital signal values and light or camera exposure, such as SDR gamma-like systems, PQ or HLG.

Transparent LED: A display with open or transmissive areas that allow some view or light through the screen.

U

Uniformity: Consistency of luminance and colour across the display and over viewing angle.

UHD: Ultra-high definition, commonly associated with 3,840 by 2,160 or 7,680 by 4,320 pixel television systems. A display accepting UHD input is not necessarily native UHD resolution.

V

Viewing angle: The range of positions over which image characteristics remain within an acceptable threshold.

Virtual production: A production method combining real-time rendering, tracking, cameras and displays, often using an LED volume for in-camera visual effects.

Video wall: A large image surface formed from multiple display units. It can use LED, LCD, projection or other technologies.

W

White point: The chromaticity treated as neutral white within a colour system.

WEEE: Waste electrical and electronic equipment. The term also refers to the regulatory regime governing collection and treatment responsibilities.

Y

Yield: The proportion of manufactured parts or assemblies that meet acceptance criteria. Yield is a central challenge in fine-pitch and MicroLED production.

Appendix C. LED display planning and procurement checklist

This checklist is designed for early planning, tender preparation and design review. It does not replace a project risk assessment, legal review or engineering design.

C.1 Purpose and audience

☐ The communication objective is written in operational terms.

☐ Primary and secondary audiences are identified.

☐ Minimum, typical and maximum viewing distances are recorded.

☐ Horizontal and vertical sightlines are shown on drawings.

☐ Essential information is separated from decorative or promotional content.

☐ Availability and downtime consequences are defined.

C.2 Content and canvas

☐ Representative content has been collected before final selection.

☐ The proposed physical size and native pixel canvas are documented.

☐ Aspect ratio and any irregular shapes are confirmed.

☐ Smallest text, line weight and dashboard details have been tested.

☐ Frame rates, SDR or HDR format and colour-space expectations are defined.

☐ A pixel map and content template will be supplied.

☐ Ownership, approval, scheduling and fallback content are defined.

C.3 Viewing environment

☐ Daylight and artificial-light conditions have been measured or modelled.

☐ Direct sun, reflections and glazing have been considered.

☐ Required operating luminance range is defined, not only maximum brightness.

☐ Black level and surface reflectance will be reviewed under representative light.

☐ Night-time brightness and any planning conditions are considered.

☐ Audience comfort and accessibility are included.

C.4 Image performance

☐ Pixel pitch is justified by content and viewing distance.

☐ Resolution is stated in physical pixels.

☐ Uniformity, white point and colour-space targets are defined where relevant.

☐ Low-grey gradients, skin tones and flat fields are part of visual testing.

☐ Viewing-angle acceptance is based on real audience positions.

☐ Camera models, frame rates, shutter settings and lenses are listed where relevant.

☐ End-to-end latency has a limit where live or interactive use requires it.

C.5 Product and environment

☐ Indoor, outdoor, semi-outdoor or protected-environment classification is clear.

☐ Environmental risks include water, condensation, dust, salt, pollution, UV and temperature.

☐ IP ratings are supported by relevant evidence and interpreted correctly.

☐ Surface protection and impact risk are considered.

☐ Noise and cooling are suitable for the space.

☐ Product dimensions, cabinet increments and tolerances are confirmed.

C.6 Structure and access

☐ A competent structural designer has clear responsibility.

☐ Loads, deflection, wind and fixing substrates are identified.

☐ Temporary and permanent conditions are considered.

☐ Front or rear service access is documented at assembly level.

☐ Safe working space, access equipment and exclusion requirements are considered.

☐ Architectural edge details, doors, speakers, sprinklers and detectors are coordinated.

☐ Future removal and replacement are included in the design.

C.7 Electrical, data and IT

☐ Maximum design load and realistic operating energy are both provided.

☐ Distribution, isolation, earthing and protective arrangements are designed by competent parties.

☐ Data routes, fibre needs and maximum distances are documented.

☐ Source, processing, controller and display responsibilities are shown in a diagram.

☐ Redundancy is described by duplicated paths and remaining single points of failure.

☐ Network ownership, access control and cybersecurity are agreed.

☐ Monitoring, alert ownership and escalation routes are defined.

C.8 Compliance and safety

☐ Applicable product regulations and conformity documentation are identified.

☐ EMC responsibilities cover the complete configuration or fixed installation.

☐ CDM, work-at-height and event duties are reviewed where applicable.

☐ Fire, building-control, insurer and landlord requirements are addressed.

☐ Planning or advertisement consent is confirmed where required.

☐ Accessibility and flashing-content controls are documented.

☐ Northern Ireland or export-market requirements are considered separately where relevant.

C.9 Support and lifecycle

☐ Warranty scope, exclusions, location and response are understood.

☐ Support hours and severity definitions match the business need.

☐ Availability of authorised support and compatible parts is documented.

☐ Software, firmware and control-system support periods are stated.

☐ Ownership and secure custody of system documentation are agreed.

☐ Acceptance records and warranty documentation will be retained.

☐ Professional support and end-of-life responsibilities are documented.

☐ RoHS, WEEE and waste-treatment responsibilities are documented.

C.10 Acceptance and handover

☐ Factory and site acceptance plans use representative content and conditions.

☐ Physical dimensions, seams and alignment have acceptance criteria.

☐ Luminance, colour and uniformity targets have a measurement method.

☐ Camera or latency tests cover the real workflow.

☐ Failover and recovery are demonstrated where specified.

☐ Asset register, drawings, declarations, manuals and training are complete.

☐ Outstanding issues, owners and deadlines are recorded.

☐ The final operating brightness and content modes are approved.

Appendix D. Common myths and better questions

Myth 1: The smallest pixel pitch is always best

Fact: A smaller pitch raises pixel density, but after it meets the content and distance requirement, other factors can dominate. Better question: What pitch produces acceptable detail with our real content from the closest important viewing position?

Myth 2: A 4K input means a 4K display

Fact: A processor can accept 4K and scale it to a lower-resolution wall. Native 4K requires 3,840 by 2,160 physical pixels. Better question: What is the display's native pixel canvas and how is the source mapped to it?

Myth 3: More nits always means a better screen

Fact: Luminance must suit the environment. Excessive output can create glare, poor comfort and unnecessary energy use. Better question: What operating range is needed for the brightest and darkest site conditions?

Myth 4: Every outdoor display uses DIP LEDs

Fact: Modern outdoor products use DIP, SMD and other architectures. Better question: What evidence shows that this complete product meets the environmental, optical and service requirements?

Myth 5: COB is automatically better than SMD

Fact: COB can provide valuable integration and surface protection, but complete products differ in optics, uniformity, yield, service model and support. Better question: Which measured outcomes does the proposed architecture improve for this application?

Myth 6: Refresh rate alone determines camera performance

Fact: Camera frame rate, shutter, panel scan, PWM, genlock, processing and brightness interact. Better question: Has the proposed system been tested with our cameras, lenses and operating modes?

Myth 7: An IP rating makes an installation weatherproof

Fact: The code applies to defined enclosure tests. Site interfaces, condensation, salt, UV, drainage and cable entries still matter. Better question: How does the complete installed system address the site's environmental risks?

Myth 8: A 100,000-hour claim is the guaranteed life of the screen

Fact: Lifetime definitions and conditions vary, and supporting assemblies age differently. Better question: What criterion, test condition, operating brightness and warranty support the claim?

Myth 9: Calibration can correct every visible mismatch

Fact: Calibration can correct some optical variation within limits; it cannot reverse physical damage, contamination or incompatible construction. Better question: Is the difference caused by correctable data, or by a physical and compatibility issue?

Myth 10: Modular construction means anyone can repair it

Fact: Modularity defines assembly boundaries, not competence or safety. Electrical, structural, optical and configuration risks remain. Better question: Which interventions are authorised, documented and supported by competent specialists?

Myth 11: LED always uses less energy than every alternative

Fact: Energy depends on screen area, output, content, duty cycle and the complete system. Better question: What is the measured annual-energy model for equivalent visual performance?

Myth 12: The most famous brand is automatically the safest choice

Fact: Suitability depends on the specific product, evidence, support route and system integration. Better question: Which proposal best meets the same documented requirements and acceptance tests?

Appendix E. References and further reading

The links below were selected for scientific authority, regulatory status, standards relevance or historical value. Manufacturer sources are used for attributed corporate history and should not be read as independent product comparisons.

E.1 History and semiconductor science

E.2 Measurement, colour and image systems

E.3 Virtual production and broadcast

E.4 MiniLED and MicroLED research

E.5 Accessibility and content safety

E.6 Enclosure protection and standards

E.7 UK regulation and official guidance

E.8 Historical company sources

E.9 Industry geography

E.10 Search publishing guidance

Contact

Questions about LED video displays?

Contact LED Perfection in Birmingham.

0121 516 0279 [email protected][email protected]