Intra-lens color and dimming apparatus

The present invention relates generally to stage lighting instruments having associated color-changing mechanisms and particularly to a light source including plural, serial lens elements and selected-wavelength modifiers that are adjustable in the plane of the modifier. A stage lighting instrument having a high-intensity light source or lamp coupled with a concave reflector, and a projection optical system having a lens system that includes a well-defined aperture stop. The lens system forms a real image of the light source near the aperture stop. A color filter and dimming system may be located within the lens system so that the color filter and dimming elements occupy a volume of space near the aperture stop and within the real image of the light source. By locating the color and dimming apparatus near the aperture stop and within the volume occupied by a real image of the light source, superior color mixing, dimming and integration is achieved using simple, unpatterned filters and a simply-shaped dimmer panel. A color filter and dimming system may alternatively be located as close to the light source as possible so that a real image of the color filter and dimming elements is formed near the aperture stop where the image of the light source is formed. The alternate location, forming a real image of the filters and dimmer, is equivalent to locating the actual color filter and dimming elements at the aperture stop. Diffusion glass elements used in a similar apparatus, located at the aperture stop, transform spotlight properties into wash-light properties in a continuously-variable manner.