Integrating sphere in the LED lamps and lanterns is correct placement method that is like

Integrating sphere light source the light uniformity, make the ball light in all parts of the inner surface is consistent, in this way, the measurement of illuminance value per unit area, take less than surface area, get the light source of luminous flux.

so, light distribution uniformity is to determine the accuracy of the measurement results in the index.

relative to the uniform glow around the incandescent lamp, energy-saving lamps, the LED because of its strong directivity, and a relatively special. This makes LED direct light in the integrating sphere surface is uneven distribution, directly lead to the different LED directly reflected light reflection characteristics of the different relative detector.

because mouth the setting of damper and the location of the probe is fixed, different reflection distribution directly show the signal fluctuation.

according to the results of the validation, common LED measurement system LED placement direction to the influence of the luminous flux measurement results are often more than 50% ( The same LED were measured in different directions, minimum and maximum signal signal difference) 。

figure 1 different Angle LED inside the ball of light distribution

analysis LED the direction of the influence on measurement accuracy is an important reason of the inner surface of the integrating sphere reflecting features.

in the ordinary LED measurement system, integrating sphere surface coatings reflectivity and lambert sex is not very ideal. Is a reflection on the low side, the other is a diffuse reflection characteristics.

this is a manifestation of integrating sphere, LED direct illuminate light through a few times after reflection and attenuation gradually, and in the light of the whole mixing process, direct illuminate light and reflected light directly accounted for a large proportion, and played a leading role. Under certain conditions, the baffle at the back of the detector will produce strong shadow effect.

the current LED test system there is no standard in using LED as light source, but use, is the stability of the drive of halogen tungsten lamp.

because the shape of the structure and standard lamp to test the LED of the difference is very big, the LED bracket light absorption effect, as well as standard LED lamp installation location and installation position difference, these will affect the measurement accuracy.

solutions in the design of LED measurement system, according to the practical use of the comprehensive optimization on the factors affecting the accuracy of measurement, to minimize the system sensitivity to the direction of the leds.

that is in the process of measurement, do not need special Angle and direction. Even in extreme conditions, the use of strong directional LED to extreme conditions of placement is used to measure the results still kept good consistency.

LED measurement system in strict accordance with the CIE standard design, the integral ball inside surface coating using Spectralon @ or Spectraflect @ of patent technology, has a very high efficiency and good lambert reflection reflection characteristics.

in the visible light range reflectivity greater than 99% and 98% respectively. Good reflective materials can ensure uniform light distribution, the direct illuminate directly reflect characteristic and the baffle of smaller shadow effect.

in the design of the damper and detecting port is optimized, the diffuse, minimize the sensitivity of the detection port to directly reflect light.

the system USES a spectral calibration of halogen tungsten lamp as a standard lamp, adopted auxiliary lights at the same time, LED to standard lamp holder used in compensation for the difference between the effects of the measurement result.

show

Φ 5 leds test conditions, the power is about 0. 35 w, light Angle is about 30 °. Used as shown in the figure below to place bearing test, respectively.

figure 2 integral ball performance verification test LED placed below

results can be seen from the results, integrating sphere system can well measuring light emitting Angle small source of light, and the result is not sensitive to placed the direction and position, can be used as ideal LED measurement system.

bober

Aladdin lighting network