Product testing standards LED optical properties

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Optical performance is particularly important for LED products, LED products, so whether we understand what photoelectric performance? Let us work together to learn about LED photoelectric products which performance testing standards.


1. The electrical characteristics

LED electrical parameters including forward current, forward voltage, reverse current and reverse voltage, the voltage meter test generally use test under constant current source power supply situation. Allow for maximum forward voltage, forward current and reverse voltage and current parameters by testing the electrical characteristics of the LED, it can also work to get the best value of the electric power of the LED.

2. The optical properties

Including luminous flux and luminous efficiency, light intensity and light intensity distribution and spectral parameters.

Luminous flux and luminous efficiency: There are generally two methods for integrating sphere method and variable angle photometer. While the latter is the most accurate test results, but takes a long time, generally use the former. When tested by an integrating sphere method can be placed in the center of the sphere LED test can also be placed in the ball wall. After the measured luminous flux, with electrical parameter tester can be measured LED luminous efficiency, which is light efficiency.

Light intensity and light intensity distribution characteristics: LED because the light intensity distribution is inconsistent, so it's with the test results from the changes in the size and the detector size varies, allowing each LED light intensity test and evaluation under the same conditions, such results more accurate.

Spectral parameters: including peak emission wavelength, spectral radiation bandwidth and spectral power distribution. The spectral characteristics of the LED can be expressed by the spectral power distribution, via spectral power distribution, can also get color parameters. Spectral power distribution tests are usually carried out through spectrophotometry, mixed monochromatic light distinguish individually measured, it can be a prism and grating spectral.

3. Switching Characteristics

Refers to light, electricity, color change characteristic LED power on and off instantly, and can be obtained through LED power variation instant working conditions, material properties, etc. through this test, to understand the power of the LED through the loss.

4. The color characteristics


The main non-ferrous coordinates, dominant wavelength, color purity, color temperature and color, etc., test methods spectrophotometry and integration.

Spectrophotometry: spectrophotometric monochromator measured by LED spectral power distribution, and use of color weighting function integral to obtain the corresponding color parameters.

Integration method: the use of a specific color filter with photodetectors directly measured color parameters.


5. Thermal Properties

Also refers to the junction temperature and thermal resistance, thermal resistance refers to the temperature difference between the heat flow along the channel on the channel power dissipation ratio, LED junction temperature refers to the PN junction temperature. There are two LED junction temperature test method is the use of infrared temperature measurement microscope or miniature thermocouple measured the surface temperature of the LED chip, and the other is to use the inverse ratio between the forward bias current to determine the junction temperature changes to determine the relationship between the LED junction temperature.