14 important parameters of LED lighting explained and essential for design

1. Forward operating current If:

　　It refers to the forward current value when the light-emitting diode emits light normally. In actual use, IF should be selected to be below 0.6·IFm according to needs.

　　2. Forward operating voltage VF:

　　The operating voltage given in the parameter table is obtained under a given forward current. It is usually measured when IF=20mA. The forward operating voltage VF of the light-emitting diode is 1.4~3V. When the external temperature rises, VF will decrease.

　　3.VI characteristics:

　　发光二极体的电压与电流的关係，在正向电压正小于某一值(叫閾值)时，电流极小，不发光。当电压超过某一值后，正向电流随电压迅速增加，发光。

　　4. Luminous intensity IV:

　　The luminous intensity of a light-emitting diode usually refers to the luminous intensity in the normal direction (for cylindrical light-emitting tubes, it refers to the axial direction). If the radiation intensity in this direction is (1/683) W/sr, then the light is 1 candela (symbol: cd). Since the luminous intensity of a general LED is small, the luminous intensity is usually measured in candela (mcd).

　　5.LED light angle:

　　-90°- +90°

　　6. Spectral half width Δλ:

　　It indicates the spectral purity of the light-emitting tube.

　　7. Half-value angle θ1/2 and viewing angle:

　　θ1/2 refers to the angle between the direction where the luminous intensity value is half of the axial intensity value and the luminous axis (normal).

　　8. Full Form:

　　The angle calculated based on the LED light-emitting solid angle is also called the plane angle.

　　9. Viewing angle:　　refers to the maximum angle at which the LED emits light. Depending on the viewing angle, the application is also different. It is also called the light intensity angle.

　　10. Half Shape:

　　The angle between the normal 0° and the maximum luminous intensity value / 2. Strictly speaking, it is the angle between the maximum luminous intensity value and the maximum luminous intensity value / 2.

　　Due to the LED packaging technology, the maximum luminous angle is not the light intensity value of the normal direction 0°. The deviation angle is introduced to refer to the angle between the angle corresponding to the maximum luminous intensity and the normal direction 0°.

　　11. Maximum forward DC current IFm:

　　The maximum forward DC current allowed. Exceeding this value may damage the diode.

　　12. Maximum reverse voltage VRm:

　　The maximum reverse voltage allowed. If this value is exceeded, the light-emitting diode may be broken down and damaged.

　　13.Working environment topm:

　　The ambient temperature range in which the light-emitting diode can work normally. If the temperature is lower or higher than this range, the light-emitting diode will not work normally and the efficiency will be greatly reduced.

　　14. Allowable power consumption Pm:

　　The maximum value of the product of the forward DC voltage across the LED and the current flowing through it. If this value is exceeded, the LED will heat up and be damaged.