Illuminating device, illuminating method and photoetching machine

The invention comprises an illuminating device, which comprises a light source and a light uniformizing system. The light uniformizing system is arranged on the optical axis of the light source, and an emergent light beam of the light source passes through the uniformizing system to realize imaging on a mask. The light source comprises an LED array and a light source controller, and the light source controller controls an inclination angle of the optical axis of the light source and an emergent light beam of each LED light source in the LED array and according to pupil energy distribution demands. By changing of the inclination angle of the optical axis of the light source and the emergent light beam of each LED light source, required energy distribution can be obtained at different pupilplane positions to realize corresponding off-axis illuminating modes. The invention further discloses an illuminating method. The illuminating method is applied to the illuminating device, an off-axisilluminating method is re