Near-field Distribution Measurement Method

Two-axis goniometer

The two-axis goniometer supports vertical angle of adding or decreasing 90 degrees’ inclination (from upward to downward) and horizontal rotation from left to right of adding or decreasing 90 degrees. The angular accuracy of the two rotating axes is 0.25 degrees.

The unique feature of mechanical design is the use of rectangular frames, which not only roughly defines the measurement plane, but also provides a more stable fixed point of light source. It can support a balanced light source which is up to 25 kg.

Some light sources may exceed the boundary of the frame, and the length of the lamp tube is 1.2m, which can also be measured. If need, the frame can be connected to the power supply of the light source which needs to be measured.

At the same time, its circuit is very simple, so it will not affect the rotation of the goniometer in the measurement process, which is NFMS-800 of the Radiant Zemax.

Imaging colorimeter

The imaging colorimeter used in the system must have sufficient spatial resolution and dynamic range to measure the details of the light source.

Because the light source is directly irradiated, ND filters may be used. The principle of choosing lens focal length is that the imaging colorimeter can capture all the details of the light source at a proper distance from the angle meter. Imaging colorimeter can measure chroma parameters, photometric parameters or radiometric parameters.

Measurement Control and Analysis Software

The control software controls the position of the angle meter, that is, the light source, relative to the imaging colorimeter, that is, the order of measurement. Its other function is to synchronize the imaging colorimeter with the goniometer.

In addition, the software can integrate all measurements into the near-field model of the light source, and at the same time, it calla out a separate measurement image.