Abstract: A projection apparatus is described, which is provided with a lamp generating a light beam with a plurality of spectral elements. The projection apparatus comprises at least one band-cut filter and moving means which change the position of said band-cut filter dynamically relative to the optical path of the light beam within the projection apparatus. The invention also relates to a method for adjusting the colour components of a light beam.

Abstract: An illumination system for videoprojectors has a light beam, a device for decomposing the light beam into a plurality of monochromatic components, a plurality of DMD devices each of which reflects one of the monochromatic components, and a plurality of devices adapted to send the monochromatic components towards the plurality of DMD devices. A second device separate from the first device recomposes the monochromatic components coming from the DMD devices into a light beam to be sent to a projection lens.

Abstract: Abstract Focusing system of the light beam for a videoprojector or comprising at least an image microforming device DMD (Digital Micromirror Device); the main feature of the system consisting in that it comprises at least an aspheric lens associated to at least an achromatic doublet. This configuration allows a substantial reduction of chromatic aberration, spherical aberration, curvature of field and the distortions, obtaining a more homogeneous illumination of the image microforming device.

Abstract: Illumination system for a videoprojector, which comprises a lighting lamp (1) emitting a light beam on a first optical axis (AB) and a projection lens (10) crossed by said light beam along a second optical axis (DE), said first optical axis (AB) and second optical axis (DE) not being substantially parallel to each other and respectively pertaining to a first plane (P1) and second plane (P2), said light beam being guided along an optical path by optic deflecting means (6; 11, 11′), which shift it from the first plane (P1) to the second plane (P2) and optic handling means (7, 8, 97, 8, 9; 12, 9′, 9, 9′″) shifting it from the first optical axis (AB) to the second optical axis (DE), said optic handling means (7, 8, 9; 7, 8, 9, 12, 9′, 9, 9′″) comprising an image forming device (9). According to the invention the geometric projection of the optical path on the first plane (P1) comprises a closed path (BB′CDX).