Led lighting working principle

- May 27, 2019-

1.The term

Wavelength: the color of light intensity change, is can be described by data, this data called wavelength. The wavelengths of light we can see range from 380 to 780nm. Unit: nano (nm)

Brightness: brightness refers to the degree of brightness of an object, and is defined as the luminous intensity per unit area. Company: nit

Light intensity: refers to the brightness of the light source. That is to say, the physical quantity of the intensity of visible light radiation emitted by the light source in a certain direction and range.

Unit: candlelight (CD)

Flux: the amount of visible light emitted by a light source per second. Unit: lumen (Lm)

Luminous effect: the flux of light emitted by the source divided by the power of the source. It is the important index that measures illuminant energy-saving. Unit: lumen per watt (Lm/w).

Color rendering: the degree to which the light source renders the object, i.e. the fidelity of the color. Usually called "color rendering index" unit: Ra.

Color temperature: the color of the light emitted by the light source is the same as that of the black body at a certain temperature. The temperature of the black body is called the color temperature of the light source.

Unit: kelvin (k).

Glare: the visual discomfort caused by objects with extremely high brightness or strong brightness contrast in the field of vision is called glare. Glare is an important factor affecting lighting quality.

Synchronization: two or more LED lights can normally operate in the way set by the program within the specified time, generally referring to the LED lights with internal control. Synchronization is the basic requirement for the coordinated change of LED lights.

Protection grade: IP protection level is the lamps and lanterns is according the characteristic of the dust, prevent moisture to classification, composed of two Numbers, the first number represents the level of dust, prevent the outside shooting of lamps and lanterns (0-6), the second number represents moisture proof, waterproof lamps and lanterns of shooting the sealing degree (0 to 8), the greater the number said the higher degree of protection.

2.The working principle: 

Led is composed of P region, N region, and the potential barrier region between them. There are extra electrons in the n-block, which are negatively charged; The barrier region is where the holes in the P region and the electrons in the N region meet, and a balance can be reached without charge. When the positive current is injected at both ends of the PN junction (that is, the input of the dc stabilized voltage power supply), the injected non-equilibrium carriers (electron-hole pairs) emit composite light during the diffusion process.

The materials used to make semiconductor light-emitting diodes are adulterated with impurities. In the state of thermal equilibrium, there are many highly mobile electrons in the n-region and many weak holes in the p-region. Due to the restriction of the barrier layer of PN junction, under normal conditions, the two cannot naturally compound. When the forward voltage is applied to the PN junction, electrons can absorb the energy of qVbi and become electrons in the high energy state, thus breaking the barrier of the PN junction and entering the side of the P region. The holes move in the opposite direction. So near the PN junction, slightly to the side of the P region, the electrons in the high energy state meet with the holes, and the radiated energy is shown in the form of light, which is the light from the LED we see.