Lamp

A lamp, comprising:

• a light source, providing an illumination light;
• a reflective unit, reflecting the illumination light;
• and
• a light modulation module, disposed on the reflective unit and located between the light source and the reflective unit, the light modulation module comprising a movable light absorbing material, wherein a region where the movable light absorbing material exists forms a light absorbing region, and a region where the movable light absorbing material is absent forms a light penetration region, the movable light absorbing material is moved to different positions respectively by applying a plurality of different electrical fields, so that sizes and locations of the light absorbing region and the light penetration region are changed, a portion of the illumination light irradiating the light penetration region penetrates through the light penetration region, is transmitted to the reflective unit, is reflected by the reflective unit, and penetrates through the light penetration region again sequentially.