How to detect the light curve of lamp lens？

1. Required equipment
Goniophotometer: core equipment that can measure the light intensity distribution of a lamp at different angles.

Darkroom or semi-darkroom: avoid ambient light interference and ensure measurement accuracy.

Power supply and voltage regulator: ensure stable operation of the lamp.

Data acquisition software: used to record and analyze light intensity data.

Calibrate the light source: calibrate the equipment regularly.

2. Measurement steps

(1) Preparation
Fix the lamp on the rotating bracket of the goniophotometer and ensure that the center of the lens is aligned with the rotation axis.

Preheat the lamp to a stable working state (such as LED requires thermal balance).

Calibrate the photometer (using a standard light source).

(2) Data acquisition
Rotation method: The goniophotometer drives the lamp to rotate around the vertical axis (horizontal angle) and the horizontal axis (vertical angle), and measures the light intensity at each angle.

Detector fixed method: The lamp is fixed and the detector rotates around it (suitable for large lamps).

The measurement range usually covers 0°~360° (horizontally) and 0°~180° (vertically). The smaller the angle interval, the higher the accuracy (such as 1° or 5°).

(3) Light curve generation

The software converts the light intensity data at each angle into a light distribution curve in polar coordinates or rectangular coordinates.

It can output iso-intensity curves, 3D light intensity distribution diagrams or beam angles (such as 50% light intensity boundary angles).

3. Key parameter analysis

Beam angle: The angle range where the light intensity drops to 50% of the central maximum value.

Light intensity distribution: Symmetry (such as circular, elliptical) and peak light intensity.

Efficiency: The transmission/refraction efficiency of the lens for the light flux of the light source.

Stray light: Light leakage in non-design directions.

4. Alternative solutions (simple measurement)

If you do not have professional equipment, you can try:

Illuminance meter method: Fix the lamp, measure with an illuminance meter at different distances and angles, and calculate the light intensity manually (the inverse square law of distance must be known).

Camera imaging method: Use a high dynamic range (HDR) camera in a dark room to capture the light spot and analyze the brightness distribution (calibration is required).