A screen is a stack
A flat display is built as a stack of thin layers, each doing a particular job. The details differ between designs, but the idea is similar: something to protect the front, something to make light or control it, something to carry electrical signals, and something to hold everything together. This article gives a general tour. Exact materials vary by manufacturer and generation, and this is not a complete or product-specific bill of materials.
The front: protection and clarity
Cover glass or plastic. Phones, tablets, and touchscreens usually have a hard transparent cover to resist scratches and impact. Specially treated glass is common, and some devices use plastic where flexibility or light weight is needed. Larger monitors and televisions may use a thinner front layer or a plastic sheet, sometimes with a coating.
Surface coatings. Thin coatings can reduce glare, scatter reflections, resist fingerprints, or repel oil. The difference between matte and glossy finishes is discussed in anti-glare and glossy screen coatings.
Touch layer. On touchscreens, a transparent conductive layer or a pattern of fine electrodes senses the finger. Transparent conductors are a special problem because most conductive materials block light; this is why the choice of material is a design challenge. Our article on how touchscreens work explains the sensing side.
The panel: where the image forms
Glass substrates. In most displays, the pixels and their switches sit on carefully made glass sheets. Glass is chosen because it is flat, stable, transparent, and tolerant of the heat used in manufacturing. Flexible displays use plastic-type films instead, as covered in flexible display materials.
Thin-film transistors. Each pixel has tiny electronic switches built from thin layers of semiconductor, insulators, and metals, patterned like a microscopic circuit. The materials used for these layers differ between designs.
Liquid crystal layer (in LCDs). A thin layer of liquid crystal material sits between two glass plates and changes how light passes through when voltage is applied. See how liquid crystals control light for how this works.
Polarizers and optical films. LCDs use polarizing films on both sides of the liquid crystal layer. Additional films spread or direct light, widen the viewing angle, or increase brightness. These are mostly plastic-based films with special coatings.
Color filters or color-conversion layers. To produce color, many LCDs use red, green, and blue filters over the subpixels. Some use layers of nanoscale light-converting particles instead; see quantum dots for an example. Pixels and subpixels explains how colors are built up.
Emissive layers (in OLED). An OLED panel has thin organic layers that emit light when current flows, placed between electrodes and sealed to keep out moisture and oxygen. See organic light emitters.
Electrodes. Transparent conductive layers carry current to pixels without blocking light. Metal lines carry signals across the panel.
The light source
In an LCD, the backlight system includes LEDs, often mounted on a metal strip or a circuit board, along with a plastic light guide that spreads the light across the screen, reflective sheets, and diffusers. These parts are covered in what backlights do in LCD screens. In older designs, fluorescent lamps played this role. Emissive panels do not need these layers because the pixels produce their own light.
The back: structure, circuits, and cooling
Metal frames and shields. Steel or aluminum frames hold the panel rigid, provide mounting points, shield electronics, and carry heat away. Their role in heat management is covered in heat, cooling, and fanless displays.
Circuit boards. The driver electronics sit on printed circuit boards made of fiberglass-type laminates with copper traces. They carry chips and components soldered on with metal alloys. Flexible ribbon connectors link the panel to the boards.
Plastic housings. Bezels and back covers are usually molded plastic, sometimes with metal reinforcement.
Adhesives and gaskets. Many layers are bonded with transparent adhesives and sealed with tapes and foams. These help the display stay thin and strong and keep out dust, but they make it harder to separate parts later. Why screens are hard to repair covers that problem.
Cables, connectors, and power supplies. These contain copper, various plastics, and other metals.
Why materials matter
Performance
The choice of glass, films, and coatings affects brightness, contrast, color, viewing angle, durability, and weight. Better optical films, for instance, can make the same backlight appear brighter from the front.
Reliability
Moisture, heat, and sunlight can attack some of the organic or adhesive layers. This is one reason sealing and protective layers matter, and a reason for the aging seen in why screens dim and shift with age.
Safety and handling
Some of the materials used in displays need careful handling at the end of life. Older screens may contain substances that are regulated in many places, and breakage can expose sharp glass. Display recycling and end of life covers this in general terms. Rules on restricted substances vary by region and change over time, so this article does not list them.
Recycling
Because layers are bonded and thin, separating them is hard. Some materials, such as aluminum, copper, and glass, can be recovered more readily. Others are present in tiny amounts, spread over large areas. Whether a given material is recovered depends on technology and cost.
Supply
A few elements and materials used in displays are produced in limited places or in small quantities, which can affect cost and availability. How this plays out changes over time, and we do not make claims about specific materials or markets here.
Newer approaches
Research and development continue on thinner, lighter, and more flexible layers, new conductors, and alternative manufacturing methods. Some of these, such as printed electronics, aim to use less material or energy in production. These ideas are changing, and none should be assumed to be on the market or to fit every use. They are covered in emerging displays and open questions.
Taking it further
The overview above is deliberately general. For details about a particular screen, the manufacturer’s documentation and regional compliance statements are better sources than a general article. For the energy and environmental effects of making and using screens, see our overview of display energy use.