GB/T 39492-2020 English PDF (GBT39492-2020)

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GB/T 39492-2020: Testing method of quantum efficiency for white LED phosphor
GB/T 39492-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 77.120.99
H 14
Testing Method of Quantum Efficiency for White LED
Phosphor
ISSUED ON. NOVEMBER 19, 2020
IMPLEMENTED ON. OCTOBER 1, 2021
Issued by. State Administration for Market Regulation;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword... 3
1 Scope... 4
2 Normative References... 4
3 Terms and Definitions... 4
4 Method Principles... 5
5 Instruments and Devices... 5
6 Test Procedures... 6
7 Expression of Test Results... 7
8 Precision... 7
9 Requirements for Test Report... 8
Testing Method of Quantum Efficiency for White LED
Phosphor
1 Scope
This Standard specifies the method principles, instruments and devices, test procedures, test
result expression, precision and test report requirements for the quantum efficiency of
phosphors used for white LEDs.
This Standard is applicable to the testing of the external quantum efficiency and internal
quantum efficiency of white LED phosphor emitting in the band range of 400 nm ~ 780 nm
when the LED chip is excited with a peak wavelength of 400 nm ~ 480 nm. The determination
range of external quantum efficiency is 0.6 ~ 0.9, and the determination range of internal
quantum efficiency is greater than 0.9.
2 Normative References
The following documents are indispensable to the application of this document. In terms of
references with a specified date, only versions with a specified date are applicable to this
document. In terms of references without a specified date, the latest version (including all the
modifications) is applicable to this document.
GB/T 8170 Rules of Rounding off for Numerical Values and Expression and Judgement of
Limiting Values
3 Terms and Definitions
The following terms and definitions are applicable to this document.
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.
Figure 1 -- Example of Quantum Efficiency Testing Device
6 Test Procedures
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.