The collimator, as the name suggests, is to shrink the beam. The collimator is an accessory of X-ray inspection equipment. The main purpose is to locate and use when setting the simulated X-ray radiation area, which can reduce the radiation dose of the patient and improve the image quality. The actual effect is to first turn on the light on the collimator, adjust the knobs in the X and Y directions of the collimator, so that the light of the collimator shines on the diaphragm of your machine, so that the size of the light field is exactly the same as the film. Then the film is ready. Since the deviation between the X-ray field and the light field must be adjusted to the minimum before the machine leaves the factory, the light field can simulate an invisible X-ray field.