The first part:? LED of common terms
Is shorthand for the English Light Emiting Diode, Chinese translated as light-emitting diodes, light emitting diodes as the name suggests is a kind of electrical energy into light energy can be electronic devices with diode characteristics.
According to the light radiation emitted by the light emitting diodes is different, can be divided into visible light emitting diodes, infrared emitting diodes, ultraviolet light emitting diodes of three. Generally, we referred to is the visible light-emitting diode light-emitting diodes.

LED optical window sum amount of light emitted per second of
Note 1: The luminous flux LED light indicates the number, the more lumens luminous greater;
Note 2: The flux units lumen (Lumen, abbreviated Lm) of measure such as: 12Lm.
Concept Clarification:
1, the flux refers to, so we can only say "light," "Sunshine of flux," and can not be said to be "stone of flux."
2, flux and cross section forever tied (for example: optical window), that is related to the volume and area.
  Such as: 650 lumens 17-inch monitor - is actually saying, "flux in the visual area of the 17-inch display is 650 lumens," "1200 lumens projector" - "on the projector lens section luminous flux of 1200 lumens. "