ARS (Angular Response System) is a test system for the angular distribution characteristics of various light sensors. The system consists of a highly collimated and parallel simulated light source (divergence angle < 0.1°) that projects a high uniformity light spot with a diameter greater than or equal to 25mm onto the light sensor under test. The system is equipped with an angle test with an angle resolution of less than 0.1° and a working range of -90° to 90°. The system software can automatically draw angle distribution and light response curves, making it the best tool for developing various light sensor module structures.