Flat-panel display

Flat screens show us pictures and words.

They are thin and light. You see them on phones and laptops. They are also on big TVs.

Some screens use a special liquid. This liquid sits between two pieces of glass. It helps make the colors we see.

Other screens use tiny lights. These lights can glow on their own. This makes the picture look very bright.

Some screens need power to work. If the power goes out, the picture fades.

But other screens are different. They can hold a picture even without power. This is how some e-readers work. It is a clever way to see things.

Flat-panel displays are electronic screens. They show us text and images.

These screens are thin and light. You can find them on phones and laptops. They are also used in trains.

There are different ways these screens work. One way uses a liquid crystal. This is called an LCD. The liquid sits between two glass plates. It uses electricity to change how light passes through.

This makes the colors we see.

Another way uses tiny lights. One type is an OLED. This stands for organic light-emitting diode. In an OLED, a special film glows when electricity flows. These screens are very common in smartphones.

Some screens are volatile. This means they need constant power. They must refresh the image many times a second. If the power stops, the image fades away.

Other screens are static. These use special materials to hold a color. A static screen can show a picture even without power.

This is how some e-readers work. The text stays on the screen even if the battery dies.

Flat-panel displays are thin electronic screens used to show text and images.

You can find them on many things like phones, laptops, and even medical equipment. These screens are much thinner and lighter than the heavy TVs used in the past. They can also show much clearer pictures with higher resolution. In the 2010s, they became very popular for portable gadgets. This is because they use less power and are easy to carry.

There are different ways these screens work to make a picture. An LCD, or liquid-crystal display, uses a thin layer of liquid crystal. This liquid is sandwiched between two glass plates with electrodes. When electricity moves through the electrodes, it changes how the liquid blocks light. Color is then made by using red, green, and blue filters.

Another type is an OLED, which stands for organic light-emitting diode. In an OLED, a special organic film glows when electricity flows through it. Some screens also use quantum dots to make colors even brighter.

People have been working on thin screens for a long time. In 1954, General Electric made a proposal for a flat-panel TV. They used ideas from their work on radar monitors. Later, the Aiken tube was produced in 1958 for military use. In 1964, scientists at the University of Illinois invented the plasma display panel. Many different people worked on these ideas for decades. These early steps helped lead to the screens we use today.

Many important inventions helped build modern display technology. In 1959, Mohamed M. Atalla and Dawon Kahng invented the MOSFET transistor. This helped lead to the thin-film transistor used in LCDs. In 1968, Hewlett-Packard introduced the first usable LED display. Later, in 1987, Ching W. Tang and Steven Van Slyke built the first practical OLED device. By 2007, Sony released the XEL-1, which was the first OLED television.

These dates show how fast technology changed.

Screens are often divided into two groups: volatile and static. Most screens we use, like smartphones, are volatile. This means they need constant power to keep the image visible. They must refresh the pixels many times every second. If the power goes out, the image will fade away.

Static screens are different because they use materials that hold their color. An e-reader uses this technology.

Even if the battery dies, the text stays on the screen.

A flat-panel display (FPD) is an electronic device used to present visual information like text or images. These displays are essential in modern life, appearing in consumer electronics, medical tools, transportation systems, and industrial equipment. Compared to the bulky cathode-ray tube (CRT) televisions of the past, flat-panel displays are much thinner and lighter. They also offer better linearity and significantly higher resolution. While older consumer CRT televisions reached a maximum of 1080i, many modern interactive panels can display 1080p or even 4K resolution.

Flat-panel technology can be categorized into two main types: volatile and static. Volatile displays, such as liquid-crystal displays (LCD), require constant electrical power to maintain an image. These screens must periodically refresh their pixels many times per second to retain their state. If the power is removed, the pixels lose their coherent state and the image fades away. In contrast, static displays use materials with bistable color states. An example is e-ink technology, which retains its content even when the power is turned off.

Liquid-crystal displays (LCD) are a very common type of volatile display. An LCD works by sandwiching a thin layer of liquid crystal between two glass plates. These plates carry transparent electrodes, and two polarizing films are placed on either side. By applying a controlled electric field between the electrodes, the display can change the polarizing properties of the liquid crystal. This is achieved through different alignment methods, such as twisted nematic (TN), in-plane switching (IPS), or vertical alignment (VA). To create colors, the display applies red, green, and blue filters to individual subpixels.

Many LCDs are actually LED-backlit, meaning they use light-emitting diodes (LEDs) as an illumination source. While older large LCDs used cold-cathode fluorescent lamps (CCFL), most modern screens use LED technology. Another advanced version is the quantum-dot light-emitting diode (QLED). This technology, used by brands like Samsung, uses quantum dots to create unique light when hit by blue LEDs. This enhances the color gamut of the LCD panel. Some displays also use organic light-emitting diodes (OLED). In an OLED, an organic compound film emits light directly in response to an electric current.

The journey toward thin screens began decades ago. In 1954, General Electric proposed a flat-panel TV based on radar monitor research. Although they published the basics, they did not build a working model at that time. In 1958, the Aiken tube became the first production flat-panel display, used mostly in military systems. That same year, the Philco Predicta was released as a relatively flat CRT setup, but it was a commercial failure. In 1964, researchers at the University of Illinois invented the plasma display panel. Plasma displays work by applying voltage to electrodes in a gas-filled gap, causing segments of gas, such as neon, to glow.

Technological breakthroughs in the mid-20th century paved the way for modern high-resolution screens. In 1959, Mohamed M. Atalla and Dawon Kahng invented the MOSFET, a type of transistor. Later, in 1962, Paul K. Weimer developed the thin-film transistor (TFT), which is a specific type of MOSFET. This was crucial because modern high-quality displays use TFT-based active-matrix displays. In 1968, Hewlett-Packard introduced the first usable LED display, which eventually replaced Nixie tubes for numeric displays. By 1987, Ching W. Tang and Steven Van Slyke at Eastman Kodak created the first practical OLED device. Finally, in 2007, Sony released the XEL-1, the world's first OLED television.

Today, flat-panel displays have almost completely replaced CRT displays as of 2016. Their ability to be lightweight and consume less power made them perfect for the rise of portable electronics. In the 2010s, they became the standard for laptops, mobile phones, and portable cameras. The development of the thin-film transistor in the 1960s and 1970s by researchers like T. Peter Brody allowed for the active-matrix LCDs we use now. These advancements have connected various fields, from the large-scale LED displays seen in arenas to the tiny screens on a smartphone.