How Plasma Displays Function

When discussing display technologies, cathode ray tube (CRT) and liquid-crystal display (LCD) technologies are often the most talked about types. While CRTs and LCDs have dominated the display market for many decades, plasma is an alternative that may be useful for certain applications. Plasma display panels (PDP) are displays that utilize small cells containing plasma for creating images, and they are an upgrade from CRT technology with their performance and characteristics. In this blog, we will discuss plasma displays, allowing you to have a better understanding of their functionality.

Plasma is a gas that contains free-flowing ions and electrons, and it can serve as the central element of a fluorescent light. During standard conditions, the gas mostly consists of uncharged particles. This means that the gas atoms all have an equal amount of protons and electrons and will have a net charge of zero. By inducing an electrical voltage to the gas, the amount of free electrons will increase. These free electronics will then collide with atoms, causing a net positive charge which results in ionization.

During the flow of current through plasma, the negatively and positively charged particles will begin to rush towards the opposite side. As positive and negative particles collide with one another, the gas atoms become excited and will emit photons as a result. The atoms that are present within plasma displays are Xenon and neon, and they will both emit ultraviolet light photons when they become excited. While these ultraviolet light photons are invisible to the human eye, they can be used to excite visible light photons so that an image may be formed on the display.

The gas atoms of a plasma display are located within cells which are contained between plates of glass. Electrodes are also placed between the glass plates and serve to separate the cells. Meanwhile, address electrodes are placed behind the cells while transparent display electrodes are placed in front. The display electrode is also insulated by a dielectric material as well as covered by a magnesium oxide protective layer. With this construction, a plasma display utilizes a grid of electrodes that span the entire screen.

To begin ionization, the plasma display utilizes its computer to charge the electrodes that intersect a particular cell. As an image may require numerous cells to be charged at once, the computer conducts ionization thousands of times a second. When induced current causes the excitement of atoms and ultraviolet photons are released, they will begin to interact with phosphor materials that coat the cell walls. In the reaction between phosphors and ultraviolet light photons, visible light photons are released.

Each pixel of the display consists of three subpixel cells, and each subpixel cell contains a different colored phosphor. These colors are red, green, and blue, and the three can be blended as needed to produce a color for the pixel. Variation in pixel color is also managed by the amount of current that passes through a cell, meaning that the display is capable of presenting the full spectrum of colors.

1. mark bogart
2. Posted on April 30, 2021
electronics

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