# Basic Concepts Of LED Test Technology

- Sep 30, 2018-

Basic concepts of LED test technology

Today to share some of the basic concepts in LED testing:

The "positive voltage" is a voltage drop generated between the two poles when the forward current of the light-emitting diode is a predetermined value.

The "reverse current" is a current that flows through the light-emitting diode when the reverse voltage across the light-emitting diode is a predetermined value.

The "peak wavelength" spectrum has the highest wavelength of radiated power.

The "half-intensity angle" is an angle at which the illuminating (or radiant) illuminating intensity is greater than or equal to half of the maximum intensity in the illuminating (or radiant) intensity distribution.

Any color of the "main wavelength" can be seen as a mixture of a certain spectral color and a reference light source (such as CIE standard light source A, B, C, etc., energy source E, standard illuminant D65, etc.) The color that comes out, this spectral color is the dominant wavelength of the color. The dominant wavelength of the color is equivalent to the hue (mental amount) of the color observed by the human eye. If the chromaticity coordinates of the LED device under test have been obtained, an equivalent energy white light source (x0=0.3333, y0 = 0.3333) can be used as the reference source to calculate the dominant wavelength of the determined color. In the calculation, according to the slope of the straight line connecting the reference light source chromaticity point and the sample color chromaticity point on the chromaticity diagram, look up the intersection of the readout straight line and the spectral trajectory to determine the dominant wavelength.

The ratio of the luminous flux dΦv contained in a small solid angle element in a given direction to the solid angle dΩ in units of candlelight (candela, cd).

The "radiation bandwidth" spectral radiation power is greater than or equal to half the maximum wavelength interval.

LED test can refer to the "CIE-127-1997 Measurement of LED" recommendation, select conditions A and B to measure the average LED specification information under near-field conditions.

Dalian Xinghai Technology Co., Ltd.