Abstract: An optical unit that directs illumination light to a plurality of digital micromirror devices that produce projection light by modulating the illumination light on an image display surface according to an image signal, and that transmits and emits the projection light, the optical unit includes: a plurality of first prisms, wherein the projection light exits a first face of a most emergence-side first prism among the first prisms; and a second prism disposed next to the first prisms, wherein the second prism includes: a 2A-th face into which the projection light enters; and a 2B-th face disposed perpendicular to an optical axis of the projection light, the projection light exits the 2B-th face, the second prism is wedge-shaped with the 2A-th and 2B-th faces not being in parallel with each other.

Abstract: An optical unit that directs illumination light to a plurality of digital micromirror devices that produce projection light by modulating the illumination light on an image display surface according to an image signal, and that transmits and emits the projection light, the optical unit includes: a plurality of first prisms, wherein the projection light exits a first face of a most emergence-side first prism among the first prisms; and a second prism disposed next to the first prisms, wherein the second prism includes: a 2A-th face into which the projection light enters; and a 2B-th face disposed perpendicular to an optical axis of the projection light, the projection light exits the 2B-th face, the second prism is wedge-shaped with the 2A-th and 2B-th faces not being in parallel with each other.

Abstract: In an optical unit, illumination light is directed to a plurality of digital micromirror devices that produce projection light by modulating the illumination light on an image display surface according to an image signal. The optical unit emits the projection light produced by the digital micromirror devices. The optical unit includes: a reflector having an illumination light reflecting face on which the illumination light is reflected; and a prism unit composed of a plurality of first prisms. The reflected illumination light enters the prism unit via a first face of a most emergence-side first prism among the first prisms and the projection light exits via the first face.

Abstract: In an optical unit, illumination light is directed to a plurality of digital micromirror devices that produce projection light by modulating the illumination light on an image display surface according to an image signal. The optical unit emits the projection light produced by the digital micromirror devices. The optical unit includes: a reflector having an illumination light reflecting face on which the illumination light is reflected; and a prism unit composed of a plurality of first prisms. The reflected illumination light enters the prism unit via a first face of a most emergence-side first prism among the first prisms and the projection light exits via the first face.

Abstract: A variable magnification projection optical system includes, in order from a magnification conjugate side to a reduction conjugate side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, a sixth lens group, and an optical stop which is arranged at any position from a front of a lens arranged closest to the magnification conjugate side in the fourth lens group to a front of a lens arranged closest to the magnification conjugate side in the fifth lens group, wherein the fourth lens group is configured to include, in order from the magnification conjugate side, two or more negative lenses and a positive lens, and wherein the following condition expressions (1), (2) and (3) are satisfied: |Et/ft|?10??(1) |EW/fW|?15??(2) 0.87?23?T/23WT?1.15??(3).

Abstract: A variable magnification projection optical system includes, in order from a magnification conjugate side to a reduction conjugate side, a first lens group, a second lens group, a third lens group, a fourth lens group, a fifth lens group, a sixth lens group, and an optical stop which is arranged at any position from a front of a lens arranged closest to the magnification conjugate side in the fourth lens group to a front of a lens arranged closest to the magnification conjugate side in the fifth lens group, wherein the fourth lens group is configured to include, in order from the magnification conjugate side, two or more negative lenses and a positive lens, and wherein the following condition expressions (1), (2) and (3) are satisfied. |ET/fT|?10??(1) |EW/fW|?15??(2) 0.87??23T/??23W?1.

Abstract: A variable-focal-length lens system for projection which achieves focusing by movement of the entire system has a second to a fourth lens group as focal-length-varying lens groups and a first lens group as a distance-compensation lens group. The second to fourth lens groups individually move in the optical axis direction to vary the group-to-group distances so as to vary the focal length of the entire system. During focusing, the first lens group moves in the optical axis direction such that, as the projection distance varies from a remote distance to a close distance, curvature of field varies to the under side.

Abstract: A variable-focal-length lens system for projection which achieves focusing by movement of the entire system has a second to a fourth lens group as focal-length-varying lens groups and a first lens group as a distance-compensation lens group. The second to fourth lens groups individually move in the optical axis direction to vary the group-to-group distances so as to vary the focal length of the entire system. During focusing, the first lens group moves in the optical axis direction such that, as the projection distance varies from a remote distance to a close distance, curvature of field varies to the under side.