What is the LED general jargon?

A:common LED jargon:
Forward current IF: It refers to the light of the light emitting diode forward current value. In actual use should be selected the IF in 0.6ifm below.
Forward voltage VF: parameter table given in the operating voltage is obtained in a given forward current. Generally IF = 20mA when measured. The light-emitting diode forward voltage VF 1.4-3v. , VF will decline when the outside temperature.
The VI characteristics: light-emitting diode voltage and current relationship, the forward voltage is less than a certain value, the forward current with voltage increasing rapidly, luminous.
Luminous intensity IV: the issue of the light-emitting diode strength fingering line (cylindrical LED tube is the luminous intensity in the direction of its axis). Radiation intensity in the direction (1/683) W / sr, emitting 1 candela (sign bit cd). General LED luminous intensity is small, so the unit of luminous intensity commonly candlelight (Candela, mcd).
LED Beam Angle: -90 ° - +90 °.
Spectral half width △ into: it represents the spectral purity of the light emitting tube.
The half-value angle of 1/2 and half of the direction of the light emitting angle of the axial direction (normal) Angle: 1/2 is the luminous intensity value of the axial intensity value.
Full-width angle: LED light-emitting solid angle converter. Also called plane angle.
Perspective: refers to the maximum angle of the LED light. The application is also different, depending on the angle of view, also called light intensity angle.
The half-width: Act / 2 the angle between 0 ° and the maximum luminous intensity value. Strictly speaking, the maximum luminous intensity value and the maximum luminous intensity value / 2 corresponding to the angle. LED packaging technology led to the maximum emission angle is not the intensity value to 0 °, the introduction of the deviation angle is an angle corresponding to the maximum luminous intensity between 0 ° angle.
Maximum forward DC current ifm: allows you to add a forward DC current. Than this value can damage the diode.
The maximum reverse current VRm: allows you to add the maximum reverse voltage exceeds this value, light-emitting diodes may be damaged breakdown.
Working environment topm: Light Emitting Diode normal working environment temperature range. Lower or higher than this temperature range, light-emitting diodes will not work, efficiency is greatly reduced.
Allow power Pm: allows you to add positive DC voltage flow through the product of the maximum of its current across the LED. Exceeds this value, LED fever, damage.