phosphor, solid material that emits light, or luminesces, when exposed to radiation such as ultraviolet light or an electron beam. Hundreds of thousands of phosphors have been synthesized, each one having its own characteristic colour of emission and period of time during which light is emitted after excitation ceases.
What does the word phosphor mean?
Definition of phosphor 1 : a phosphorescent substance. 2 : a luminescent substance that emits light when excited by radiation (such as electrons) and is used especially in fluorescent lamps and cathode-ray tubes.
What is an inorganic phosphor material?
Inorganic phosphors normally consist of a crystalline host material doped with a relatively small amount of rare earth or transition metal ions, called activators, which convert light from shorter wavelength to longer wavelength (Stokes shift) via electronic transitions.
What is the purpose of the phosphor layer?
Phosphor layers provide most of the light produced by fluorescent lamps, and are also used to improve the balance of light produced by metal halide lamps. Various neon signs use phosphor layers to produce different colors of light.
Are phosphors toxic?
Phosphor is a chemically engineered powder that comes from various natural elements. It is not toxic and does not contain mercury. Phosphor does not contain the element phosphorus.
How do phosphorescent materials work?
Basically, a phosphorescent material is “charged” by exposing it to light. The material absorbs light and releases the stored energy slowly and at a longer wavelength than the original light. Fluorescent materials absorb energy and immediately release light.
What is phosphor persistence?
Measure of the time for a phosphor’s brightness to drop to one-tenth of its initial value; the tendency of a phosphor to continue to emit light when no longer excited by an electron beam. The higher the persistence, the better the quality of the display.
What is the phosphor in fluorescent lights?
In a fluorescent lamp, the emitted light is generated by a phosphor layer which is deposited on the inner side of a glass tube. The phosphor is excited by ultraviolet light, which is typically generated with a gas discharge in low-pressure mercury vapor.
Why phosphor screen is used in CRT?
The phosphor screen emites photons if accelerated electrons hit the material. The most common use of phosphor screens are cathode ray tube displays which are used in the early TV’s and oscilloscopes. The phosphor screen converts accelerated electrons into photons.
What is the meaning of phosphor?
Definition of phosphor. 1 : a phosphorescent substance. 2 : a luminescent substance that emits light when excited by radiation (such as electrons) and is used especially in fluorescent lamps and cathode-ray tubes.
How is phosphor recycled?
Phosphor recycle (as practiced by Solvay Rare Earth Systems) consists of two main steps: recovery of phosphor powder from end-of-use fluorescent lamps production of pure individual rare earth oxide and phosphate powders from the recovered powder.
What are the phosphors in LED light bulbs?
Phosphors are materials that have the ability to absorb the high energy (short wavelength) emitted by the LED chip and down-convert them into lower energy (longer wavelength). Jacques Lucas, William Davenport, in Rare Earths, 2015
What is the difference between phosphor and fluorescent?
Phosphor. Phosphorescent materials are known for their use in radar screens and glow-in-the-dark materials, whereas fluorescent materials are common in cathode ray tube (CRT) and plasma video display screens, fluorescent lights, sensors, and white LEDs .
