LED main parameters and electrical, optical, thermal characteristics

The LED electronic display is a photovoltaic device that uses a compound material to form a pn junction. It has the electrical properties of a pn junction device: IV, CV, and optical: spectral response, luminescence, directional, time, and thermal properties.

1, LED electrical characteristics

1.1IV Characterization The main parameters of the LED chip pn junction preparation performance. The IV characteristics of LEDs have non-linear, rectifying properties: unidirectional conductivity, that is, the application of a positive bias exhibits low contact resistance, and vice versa.

(1) Positive dead zone: (Fig. oa or oa' segment) Point a is the turn-on voltage for V0. When V < Va, the applied electric field overcomes a lot of carrier field electric field diffusion, and R is very Large; turn-on voltage is different for different LEDs, GaAs is 1V, red GaAsP is 1.2V, GaP is 1.8V, and GaN is 2.5V.

(2) Forward working area: current IF is exponential with applied voltage

IF=IS(eqVF/KT-1)------------------------- IS is the reverse saturation current.

When V>0, the positive working area IF of V>VF rises with the VF index IF=ISeqVF/KT

(3) Reverse dead zone: pn junction plus reverse bias when V<0

When V=-VR, when the reverse leakage current IR (V=-5V), GaP is 0V and GaN is 10uA.

(4) Reverse breakdown region V<-VR, VR is called reverse breakdown voltage; VR voltage corresponds to IR is reverse leakage current. When the reverse bias voltage is increased such that V < - VR, a sudden increase in IR occurs and a breakdown phenomenon occurs. The reverse breakdown voltage VR of various LEDs is also different due to the variety of compound materials used.

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