The shortest wavelength X-rays from 0.1~0.01nm
These are ions that have lost electrons. Holes can move through a crystal lattice by taking an electron from an adjacent ion and repeating the process indefinitely. A phenomenon discovered in semi-conductor technology.
The basic material into which an activator is added.
The emission of light by a heated object, e.g. light bulb filament.
Part of the electromagnetic spectrum extending from the limits of red visibility, i.e. 700nm~1mm.
An ion is an atom, molecule or radical that has either lost or gained valence electrons.
The radius of an ion. Used to check if an activator will substitute into a host lattice; ± 10~15% is a guide figure.
Joint Electron Device Engineering Council. A classification system for CRT phosphors.
Named after Lord Kelvin (1824-1907). A temperature scale starting from absolute zero and with the same magnitude as Celsius.
An impurity within a phosphor that destroys luminescence, e.g. Ni.
Greek letter Lambda, the symbol for wavelength.
A phosphor used for general fluorescent lighting, excited by 254nm and unaffected by mercury vapour.
A laser is a device that produces light at a specific wavelength. This light is emitted coherently, allowing the beam to stay narrow and focus on a tiny spot. The initial resonance is produced by materials as diverse as YAG , dyes or metal vapours.
A doped semiconductor that emits light when electric current passes through it.
A unit of luminous flux that measures the total quantitiy of visible light emitted by a source. The value is weighted by the response of the human eye. It cannot therefore be used to measure ultraviolet or infrared light. One candela of light emitting uniformly in all directions produces 4π lumens.
A measure of Luminous Efficacy, lumens emitted per watt of input power. It is an indication of how well a light source is converting power into light.
The ability of a lamp or device to maintain its initial output.
Mega electron volts.
Another term for flux.
The amount of a substance containing a number of constitutive particles (e.g. atoms or particles) equal to the Avagadro constant (~6.022 x 1023).
A way of defining the activator concentration in a host, e.g. Y1.9Eu0.1O3. 0.1*100% / 2 = 5 mole % or 5m/o
The shape and structure of a crystal.
Internal energy transitions that do not result in light, generally referring to losses to heat rather than sensitiser actions.
E(λ) = Aλ-5 /exp(B/Tc)-1 Where A & B are constants, λ is the emission wavelength and Tc is the temperature of the Black Body.
A plasma is an ionised gas or vapour that is formed at low pressures when high voltages are placed across the gas. When gases are ionised they conduct electricity and emit characteristic lines of radiation.
Plasma Display Panel. A flat display panel consisting of two flat sheets (at least one is glass), sandwiching spacers that confine individual cells filled with an inert gas mixture. The phosphor is deposited inside the outer glass sheet and is illuminated by the radiation produced by the inert gas plasma and electrode in a similar fashion to a neon tube.
Another term for afterglow.
A packet of electromagnetic energy with wave-like properties.
A single “packet” of light radiation of any wavelength. Light behaves as both a wave and a particle in some situations. The exact nature of light has not been completely defined.
This refers to the region of physical effects that are on the level of individual electrons and quanta of light, on an atomic or molecular level.
This is the simple expression, given as a percentage: [Quanta of light out] / [Quanta of light in], e.g. 90 quanta of visible light emitted / 100 quanta of UV absorbed means the phosphor has a quantum efficiency of 90%. N.B. please note that this applies to light of all wavelengths and has nothing to do with the eye’s perception of brightness.
Resistance of a capacitor or inductor to alternating current.
The process whereby excited electrons reach equilibrium in their excited state before they return to their original energy level.
A secondary activator which absorbs additional excitation energy and transmits it directly to the primary activator to enhance efficiency.
The release of trapped electrons in a storage phosphor; usually by IR.
The longer wavelength X-rays from 1~10nm
Exact proportions and relationships of the elements of a substance.
The energy of absorption is higher than the energy of emission.
The distance between the excitation peak and the emission peak of a phosphor. Measured in nm, eV or Wavenumber (cm-1).
The ability of a material to store electrons in traps until they are released by stimulating radiation such as infrared.
Tube Engineering Panel Advisory Council. A classification system for CRT phosphors.
Sites within a crystal where impurity ions or vacancies exist. They trap electrons for variable lengths of time, depending on the phosphor. The decay time is thus directly related to the degree of trapping.
The release of stored light by mechanical action.
Another name for an anti-stokes phosphor.
Ultra Violet radiation between 320nm and 400nm
Ultra Violet radiation between 260nm and 320nm
Ultra Violet radiation between 200nm and 260nm
These are imperfections or discontinuities within a phosphor crystal lattice that may affect the performance of the material.
Vacuum Ultraviolet. Ultraviolet radiation between 100nm and 200nm. This is absorbed by the oxygen in the air and so can only radiate within an oxygen-free gas or a vacuum.
λ. The distance between successive crests of a wave, measured in nm. N.B. Wavelength is inversely proportional to energy.
υ = υ/c or 1/λ it is the number of waves/cm. It is often used by spectroscopists as it is proportional to energy.
Yttrium Aluminium Garnet.