Phosphor in the context of Cold cathode fluorescent lamp

A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms on an oscilloscope, a frame of video on an analog television set (TV), digital raster graphics on a computer monitor, or other phenomena like radar targets. A CRT in a TV is commonly called a picture tube. CRTs have also been used as memory devices, in which case the screen is not intended to be visible to an observer. The term cathode ray was used to describe electron beams when they were first discovered, before it was understood that what was emitted from the cathode was a beam of electrons.

In CRT TVs and computer monitors, the entire front area of the tube is scanned repeatedly and systematically in a fixed pattern called a raster. In color devices, an image is produced by controlling the intensity of each of three electron beams, one for each additive primary color (red, green, and blue) with a video signal as a reference. In modern CRT monitors and TVs the beams are bent by magnetic deflection, using a deflection yoke. Electrostatic deflection is commonly used in oscilloscopes.

Additive color or additive mixing is a property of a color model that predicts the appearance of colors made by coincident component lights, i.e. the perceived color can be predicted by summing the numeric representations of the component colors. Modern formulations of Grassmann's laws describe the additivity in the color perception of light mixtures in terms of algebraic equations. Additive color predicts perception and not any sort of change in the photons of light themselves. These predictions are only applicable in the limited scope of color matching experiments where viewers match small patches of uniform color isolated against a gray or black background.

Additive color models are applied in the design and testing of electronic displays that are used to render realistic images containing diverse sets of color using phosphors that emit light of a limited set of primary colors. Examination with a sufficiently powerful magnifying lens will reveal that each pixel in CRT, LCD, and most other types of color video displays is composed of red, green, and blue light-emitting phosphors which appear as a variety of single colors when viewed from a normal distance.

Primary colors are colorants or coloured lights that can be mixed in varying amounts to produce a gamut of colors. This is the essential method used to create the perception of a broad range of colors in, e.g., electronic displays, color printing, and paintings. Perceptions associated with a given combination of primary colors can be predicted by an appropriate mixing model (e.g., additive, subtractive) that uses the physics of how light interacts with physical media, and ultimately the retina to be able to accurately display the intended colors.

The most common colour mixing models are the additive primary colors (red, green, blue) and the subtractive primary colors (cyan, magenta, yellow). Red, yellow, and blue are also commonly taught as primary colors (usually in the context of subtractive color mixing as opposed to additive color mixing), despite some criticism due to its lack of scientific basis.

In electrical engineering, a light-emitting diode (LED) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.

Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red.

A fluorescent lamp, or fluorescent tube, is a low-pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor, to produce ultraviolet and make a phosphor coating in the lamp glow. Fluorescent lamps convert electrical energy into visible light much more efficiently than incandescent lamps, but are less efficient than most LED lamps. The typical luminous efficacy of fluorescent lamps is 50–100 lumens per watt, several times the efficacy of general lighting incandescent bulbs with comparable light output, which is on the close order of 16 lm/W.

Fluorescent lamp fixtures are more costly than incandescent lamps because, among other things, they require a ballast to regulate current through the lamp, but the initial cost is offset by a much lower running cost. Compact fluorescent lamps (CFL) made in the same sizes as incandescent lamp bulbs are used as an energy-saving alternative to incandescent lamps in homes.

The shadow mask is one of the two technologies used in the manufacture of cathode-ray tube (CRT) televisions and computer monitors which produce clear, focused color images. The other approach is the aperture grille, better known by its trade name, Trinitron. All early color televisions and the majority of CRT computer monitors used shadow mask technology. Both of these technologies are largely obsolete, having been increasingly replaced since the 1990s by the liquid-crystal display (LCD).

A shadow mask is a metal plate punched with tiny holes that separate the colored phosphors in the layer behind the front glass of the screen. Shadow masks are made by photochemical machining, a technique that allows for the drilling of small holes on metal sheets. Three electron guns at the back of the screen sweep across the mask, with the beams only reaching the screen if they pass through the holes. As the guns are physically separated at the back of the tube, their beams approach the mask from three slightly different angles, so after passing through the holes they hit slightly different locations on the screen.

A vector monitor, vector display, or calligraphic display is a display device used for computer graphics up through the 1970s. It is a type of CRT, similar to that of an early oscilloscope. In a vector display, the image is composed of drawn lines rather than a grid of glowing pixels as in raster graphics. The electron beam follows an arbitrary path, tracing the connected sloped lines rather than following the same horizontal raster path for all images. The beam skips over dark areas of the image without visiting their points.

Some refresh vector displays use a normal phosphor that fades rapidly and needs constant refreshing 30-40 times per second to show a stable image. These displays, such as the Imlac PDS-1, require some local refresh memory to hold the vector endpoint data. Other storage tube displays, such as the popular Tektronix 4010, use a special phosphor that continues glowing for many minutes. Storage displays do not require any local memory. In the 1970s, both types of vector displays were much more affordable than bitmap raster graphics displays when megapixel computer memory was still very expensive. Today, raster displays have replaced nearly all uses of vector displays.

A vacuum fluorescent display (VFD) is a display device once commonly used on consumer electronics equipment such as video cassette recorders, car radios, and microwave ovens.

A VFD operates on the principle of cathodoluminescence, roughly similar to a cathode-ray tube, but operating at much lower voltages. Each tube in a VFD has a phosphor-coated carbon anode that is bombarded by electrons emitted from the cathode filament. Each tube in a VFD is a triode vacuum tube because it also has a mesh control grid.

A mercury-vapor lamp is a gas-discharge lamp that uses an electric arc through vaporized mercury to produce light. The arc discharge is generally confined to a small fused quartz arc tube mounted within a larger soda lime or borosilicate glass bulb. The outer bulb may be clear or coated with a phosphor; in either case, the outer bulb provides thermal insulation, protection from the ultraviolet radiation the light produces, and a convenient mounting for the fused quartz arc tube.

Mercury-vapor lamps are more energy efficient than incandescent lamps with luminous efficacies of 35 to 55 lumens/watt. Their other advantages are a long bulb lifetime in the range of 24,000 hours and a high-intensity light output. For these reasons, they are used for large area overhead lighting, such as in factories, warehouses, and sports arenas as well as for streetlights. Clear mercury lamps produce a greenish light due to mercury's combination of spectral lines. This is not flattering to human skin color, so such lamps are typically not used in retail stores. "Color corrected" mercury bulbs overcome this problem with a phosphor on the inside of the outer bulb that emits at the red wavelengths, offering whiter light and better color rendition.

Neon lighting consists of brightly glowing, electrified glass tubes or bulbs that contain rarefied neon or other gases. Neon lights are a type of cold cathode gas-discharge light. A neon tube is a sealed glass tube with a metal electrode at each end, filled with one of a number of gases at low pressure. A high potential of several thousand volts applied to the electrodes ionizes the gas in the tube, causing it to emit colored light. The color of the light depends on the gas in the tube. Neon lights were named for neon, a noble gas which gives off a popular orange light, but other gases and chemicals called phosphors are used to produce other colors, such as hydrogen (purple-red), helium (yellow or pink), carbon dioxide (white), and mercury (blue). Neon tubes can be fabricated in curving artistic shapes, to form letters or pictures. They are mainly used to make dramatic, multicolored glowing signage for advertising, called neon signs, which were popular from the 1920s to 1960s and again in the 1980s.

The term can also refer to the miniature neon glow lamp, developed in 1917, about seven years after neon tube lighting. While neon tube lights are typically meters long, the neon lamps can be less than one centimeter in length and glow much more dimly than the tube lights. They are still in use as small indicator lights. Through the 1970s, neon glow lamps were widely used for numerical displays in electronics, for small decorative lamps, and as signal processing devices in circuitry. While these lamps are now antiques, the technology of the neon glow lamp developed into contemporary plasma displays and televisions.

Platinocyanide, also known as tetracyanoplatinate (IUPAC), cyanoplatinate, or platinocyanate, is a polyatomic ion with the molecular formula [Pt(CN)₄]. The name also applies to compounds containing this ion, which are salts of the hypothetical platinocyanic acid (sometimes platinocyanhydric acid).

Barium platinocyanide, Ba[Pt(CN)₄], is a phosphor and a scintillator. It fluoresces green in the presence of x-rays and gamma rays. It was important in the discovery of X-rays, and in the development of the fluoroscope.