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LED luminous flux
- Jul 31, 2017 -

The luminous flux measurement 

is carried out on the turntable of the variable angle photometer, which rotates the LED on the turntable. The turntder rotates ± 90 degrees around its vertical axis on its horizontal plane. The LED rotates 360 degrees around the measuring axis on the vertical plane. The control of the corners on the horizontal plane and the vertical plane is achieved by means of a stepping motor. The turntable is free to move on the rails, and when measuring the standard lamp, the turntable should leave the guide rail.


When measuring

the turntable rotates about the vertical axis on the horizontal plane, the stepping angle is 0.9 °, the positive direction is 90 ° and the reverse direction is 90 °. LED itself is also rotating, in each horizontal angle, the vertical plane every 18 ° for a signal acquisition, turn 360 ° after a total of 20 data collected, according to the following formula to calculate the total luminous flux.


If the market rotation 0 ° ~ 90 °, the small disk to 0 ° ~ 360 ° can be. But the market rotation 0 ° ~ 

90 °, there may be uneven installation of LED (asymmetric) and cause errors, so the best solution is the market turn -90 ° ~ 0 ° ~ 90 °, small disk is still 0 ° ~ 360 °, the range of 0 ° ~ 90 ° and -90 ° ~ 0 ° within the absolute range of the absolute value of the illumination value of the average value as 0 ° ~ 90 ° within the value.


The second method of LED total luminous flux measurement is the integral method. The 

advantage of this method is simple, but the measurement accuracy is not high. The total luminous flux of the LED is calculated by calculating the luminous flux Φs, Φs = I s · A / I 2 of the standard lamp (light intensity value I s) from the integrating sphere in the incident window area (incident window area A)


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