GB/T 39492-2020Testing method of quantum efficiency for white LED phosphor (English PDF)

3.1 External quantum efficiency

The ratio of the total number of photons corresponding to the fluorescence emitted by a luminescent material when excited to the total number of photons irradiated onto the phosphor sample during excitation, which is used to determine the conversion efficiency of phosphor to the incident light source.

3.2 Internal quantum efficiency

The ratio of the total number of photons corresponding to the fluorescence emitted by a luminescent material when excited to the total number of photons absorbed when excited, which is used to determine the conversion efficiency of phosphor to the absorbed light source.

3.3 Sample cell

D---detection system; S---sample system; H1---heating system; H2---heating control system.

NOTE 1: the light source system consists of an excitation light source and an excitation monochromator.

NOTE 2: the sample system consists of an integrating sphere and a sample cell.

NOTE 3: the detection system consists of a spectroscope, a detector, an amplifier and a signal processing unit. The detection system separates the signals required for testing, realizes the conversion between optical signals and electrical signals, and converts the light intensity of each measurement wavelength into the number of photons to perform data processing.

NOTE 4: the heating system consists of a heating unit and a heating control unit.

6.1 Sample Preparation

Put an appropriate amount of blank sample or powder to be tested into the sample cell, use a flat glass to flatten and compact the sample, and use a cover glass and cap to cover the sample plate. It is required that after each loading of sample, the luminescence test surface of the sample shall be flat and highly uniform.

6.2 Test

6.2.1 Turn on the equipment system and pre-heat for 30 minutes.

6.2.2 Place the sample cell or white diffuser containing the blank sample on the sample holder, use the set excitation light to irradiate it, and carry out the test to obtain the total number of light quanta (La) from the excitation source reaching the sample, and the number of background light quanta (Ea) in the fluorescence band. When using the white diffuser, the same cover glass must be placed on the sample. When using the sample cell, the blank sample and the powder to be tested must use the sample cell and cap of the same specifications.

6.2.3 Place the sample plate to be tested on the sample holder, use the same excitation light to excite it, and click TEST to obtain the data of the total number of light quanta (Lc) of the remaining excitation light after absorption by the sample under test and the number of light quanta (Ec) of the sample phosphor (calculated in accordance with the band range of 400 nm ~ 780 nm). Carry out the measurement three times in parallel and take the arithmetic mean. […]